Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “PROGESTERONE”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 721 records · Page 40Linked to original sources
PubMed1976

Gonadotrophin stimulation of progesterone synthesis by midpregnancy mouse ovarian cells in vitro.

The ability of cultured midpregnancy mouse ovarian cells to synthesize progesterone de novo and from oxogenous pregnenolone has been assessed. The conversion of pregnenolone to progesterone is almost completely blocked by cyanoketone, a known inhibitor of delta5,3beta-hydroxysteroid dehydrogenase (3beta-HSD) activity, but is unaffected by aminoglutethimide, which inhibits the cholesterol side-chain cleavage enzyme complex (desmolase). Since there is little metabolism of the formed progesterone, the ability of ovarian cells to convert exogenous pregnenolone to progesterone in vitro reflects the activity of 3beta-HSD in these cells. Cultured ovarian cells are also capable of endogenous progesterone production in the absence of added pregnenolone, although the absolute amount of progesterone produced is considerably less than that produced from exogenous pregnenolone. Since endogenous progesterone accumulation is almost completely blocked by the addition of aminoglutethimide to the culture medium, it is concluded that this response does represent de novo progesterone synthesis. Neither bovine luteinizing hormone (LH) nor human chorionic gonadotrophin (hCG) affects 3beta-HSD activity in cultured ovarian cells. The ability of the cells to secrete or to further metabolize the progesterone formed is also unaffected. However, both LH and hCG stimulate endogenous progesterone production within one hour of their addition to the culture medium. The stimulation, 2-10 fold in several experiments, can be maintained for at least six days of culture, and is not a result of an increase in the growth rate of the ovarian cells. As would be expected, the stimulation is blocked by the addition of aminoglutethimide to the culture medium. Taken together, these facts suggest that gonadotrophic hormones stimulate progesterone production by ovarian cells specifically by their action at steps prior to the conversion of pregnenolone to progesterone.

Aminoglutethimide↗
PubMed1976

Metabolic clearance and production rates of progesterone in non-pregnant and pregnant baboons (Papio papio).

The metabolic clearance rate (MCR) of progesterone was examined in the baboon to determine whether the increased serum progesterone concentrations during gestation result from increased production or decreased clearance. MCR was determined by constant infusion of [3H]progesterone in 6 non-pregnant baboons and 13 pregnant animals, between 58 and 175 days gestation. Progesterone MCR (mean+/-SE) was significantly greater in pregnant (1316+/-105 1/day, p less than 0.025; 87.3 +/- 6.2 1/day/kg, p less than 0.01) than in non-pregnant animals (893 +/- 75 1/day; 53.1 +/- 3.5 1/day/kg). There was no correlation between progesterone MCR and gestational age. Mean (+/- SE) progesterone MCR was similar during the follicular (938+/-119 1/day; 58.8+/-3.8 1/day/kg) and luteal (802+/-78 1/day; 52.4+/-6.8 1/day/kg) phases of the menstrual cycle. Serum progesterone concentrations (mean +/- SE, determined by radioimmunoassay, were 11.3+/-1.2 ng/ml in pregnant animals and 5.9+/-2.2 ng/ml during the luteal phase of the menstrual cycle. The mean (+/- SE) calculated progesterone production rates (MCR X serum progesterone concentration) were 4.57+/-1.74 mg/day during the luteal phase of the menstrual cycle and 15.26+/-2.48 mg/day during the last two-thirds of gestation. Thus, increased serum progesterone concentrations in pregnant baboons reflect enhanced production rather than decreased clearance. This is analogous to humans, but contrasts with rhesus monkeys, in which production is not increased during pregnancy. The elevated baboon progesterone MCR, despite increased serum corticosteroid binding capacity, indicates that other factors such as changes in maternal metabolism may also be important in regulating progesterone clearance.

Animals↗
PubMed1994

Individual and combined effects of relaxin, estrogen, and progesterone in ovariectomized gilts. I. Effects on the growth, softening, and histological properties of the cervix.

Marked growth and softening of the uterine portion of the cervix occur during the last third of the 115-day gestation period in the gilt. These changes in the cervix are temporally correlated with elevated blood levels of relaxin, estrogen, and progesterone. We recently demonstrated that relaxin plays a major role in promoting both the growth and softening of the cervix that occur in pregnant gilts. The roles of estrogen and progesterone in these cervical changes remain poorly understood. Accordingly, this study determined the influence of relaxin, estrogen, and progesterone, individually and in combination, on cervical growth and softening in gilts. Fifteen days after ovariectomy, six to nine nonpregnant, sexually mature gilts were assigned to one of the following eight treatment groups: ovariectomized controls, relaxin treated, estrogen treated, progesterone treated, estrogen plus relaxin treated, progesterone plus relaxin treated, estrogen plus progesterone treated, and progesterone plus estrogen plus relaxin treated. Treatment was given for 10 days, with doses of relaxin (0.5 mg, four times daily), estradiol benzoate (1 mg, twice daily), and progesterone (50 mg, twice daily) selected to provide blood levels resembling those between days 100-110 of gestation. The growth, softening, and histological characteristics of the cervices were determined. Treatment with relaxin significantly increased the growth and softening and altered the histological characteristics of the uterine portion of the cervix in the absence of steroid treatment. Estrogen treatment alone increased cervical growth, but when given in combination with relaxin, estrogen did not augment relaxin's ability to increase either cervical growth or softening. Progesterone alone had little or no effect on the growth or softening of the uterine portion of the cervix. Unexpectedly, when given in combination with relaxin, progesterone augmented markedly relaxin's effects on softening and alteration of the histological characteristics of the cervix. In conclusion, this study is consistent with recent reports that relaxin promotes both the growth and softening of the cervix in the pig. Additionally, this study provides evidence that estrogen and relaxin act independently to promote the growth of the cervix in gilts, whereas progesterone acts in concert with relaxin to promote softening of the cervix and a reduction in the organization and density of cervical collagen fibers. This study provides evidence that relaxin, estrogen, and progesterone all very likely play important roles in the modifications of the cervix that occur during late pregnancy in the gilt.

Animals↗
PubMed1994

Individual and combined effects of relaxin, estrogen, and progesterone in ovariectomized gilts. II. Effects on mammary development.

Marked development of the mammary parenchyma (ducts, lobules, and alveoli) occurs during the last third of the 115-day gestation period in the gilt. These changes in the mammary gland are temporally correlated with elevated blood levels of relaxin, estrogen, and progesterone. We recently demonstrated that relaxin plays a major role in promoting the development of the mammary parenchyma that occurs in pregnant gilts. The roles of estrogen and progesterone in the mammary gland in gilts remain poorly understood. Accordingly, this study determined the influence of relaxin, estrogen, and progesterone, individually and in combination, on mammary development. Fifteen days after ovariectomy, six to eight nonpregnant sexually mature gilts were assigned to one of the following eight treatment groups: ovariectomized controls, relaxin treated, estrogen treated, progesterone-treated, estrogen plus relaxin treated, progesterone plus relaxin treated, estrogen plus progesterone treated and progesterone plus estrogen plus relaxin treated. Treatment was given for 10 days, with doses of relaxin (0.5 mg, four times daily), estradiol benzoate (1 mg, twice daily), and progesterone (50 mg, twice daily) selected to provide blood levels similar to those occurring between days 100-110 of gestation. The fourth mammary gland from the anterior end was collected. The cross-sectional area of the parenchymal tissue was used to measure the extent of parenchymal development. To examine mammary parenchymal development in more detail, the effect of hormone treatment on lobulo-alveolar development was conducted using morphometric analysis. Relaxin alone had little effect on mammary development, and estrogen alone stimulated mammary development only modestly. In contrast, combined treatment with estrogen and relaxin stimulated mammary development markedly. Progesterone alone had no effect on lobulo-alveolar development, but, surprisingly, when administered in combination with relaxin, progesterone reduced the organization of the collagen fibrils of the mammary stroma. In conclusion, this study is consistent with recent reports that relaxin plays an important role in the development of the mammary gland in gilts. Moreover, it demonstrates that relaxin acts in concert with estrogen to stimulate development of the mammary parenchyma. Finally, this study demonstrates that relaxin in concert with progesterone decreases the organization of the collagen matrix surrounding the growing mammary gland. This study is consistent with the view that relaxin, estrogen, and progesterone all very likely play roles in the development of the mammary gland in gilts.

Animals↗
PubMed1982

Simultaneous measurement of progesterone and androgen receptors in human prostate: a microassay.

The characteristics of binding of radiolabeled progesterone, promegestone [17 alpha,21-dimethyl-19-nor-4,9-pregnadiene-3,20-dione (R5020)], medroxyprogesterone acetate (4-pregnen-6 alpha-methyl-17 alpha-ol-3,20-dione acetate), and methyltrienolone [17 beta-hydroxy-17 alpha-methyl-4,9,11-estratriene-3-one (MT)] to the progesterone receptor in human prostatic cytosol have been compared. MT binds to both androgen and progesterone receptors with high affinity (Kd = 0.9 and 0.6 nM, respectively). The binding of MT to the progesterone receptor can be blocked by adding an excess of unlabeled triamcinolone acetonide [9 alpha-fluoro-11 beta, 16 alpha, 17 alpha,21-tetrahydroxy-1,4-pregnadiene-3,20-dione-16,17-acetonide (TAC)]. The difference between the binding of [3H]MT in the absence and presence of TAC (i.e. [MT - (MT + TAC)] represents specific binding of MT to the progesterone receptor. Ligand specificity studies demonstrated that this binding was typical of a progesterone receptor. Furthermore, progesterone receptor levels measured in this way were comparable to those obtained using progesterone, R5020, or medroxyprogesterone acetate as labeled ligands. Progesterone receptor quantitation from the difference MT - (MT + TAC) is of particular advantage when simultaneous quantitation of progesterone and androgen receptors is desired in small tissue specimens since only three sets of incubations are required: [3H]MT, [3H]MT plus unlabeled TAC, and [3H]MT plus unlabeled MT (to measure nonspecific binding). Conditions are described for the application of this methodology to a microassay. A marked underestimate of progesterone receptor content was observed when incubation was terminated with hydroxylapatite compared to that measured when dextran-coated charcoal was used. The presence of comparable amounts of progesterone and androgen receptors in human prostatic cytosol deserves further investigation.

Binding, Competitive↗
PubMed1991

Lymphokines, including interleukin-2, alter gonadotropin-stimulated progesterone production and proliferation of human granulosa-luteal cells in vitro.

The effects of human interleukin-1 (IL-1) and IL-2 on human granulosa-luteal cell progesterone production were examined with or without hCG stimulation in vitro. Human granulosa-luteal cells were recovered from follicular fluid obtained from women undergoing in vitro fertilization procedures and cultured for up to 7 days before supernatant progesterone level measurement. Lymphokine-rich conditioned medium was prepared from mitogen-stimulated human peripheral blood leukocytes (HPL-CM). The influence of HPL-CM on both granulosa-luteal cell progesterone production and cell growth was inhibitory. In contrast, supernatants of the IL-2-producing cell line MLA-144 (MLA-CM) stimulated both basal progesterone secretion and cell proliferation. Human recombinant IL-2 (from 0.1-100 IU) alone did not change progesterone levels, compared to control values, after 24 h of cell culture. However, 1, 10, and 100 IU IL-2 significantly inhibited progesterone secretion from cells stimulated by 5 IU hCG (P less than 0.01). The enhanced progesterone levels stimulated by forskolin were also significantly inhibited by 10 IU IL-2 (P = 0.01). This effect was not mediated through decreased cAMP, since the forskolin-enhanced cAMP level was not influenced by IL-2, IL-1, with or without hCG, did not show any effect on progesterone production during either 24 or 48 h of cell culture. It is concluded that 1) human recombinant IL-2 significantly inhibits progesterone production stimulated by hCG in human granulosa-luteal cells; 2) IL-2 also had a marked inhibitory effect on forskolin-induced progesterone release, but did not influence the increased cAMP level stimulated by forskolin; 3) the inhibitory influence of IL-2 on progesterone synthesis may be down-stream in the signal transduction pathway from cAMP activation; and 4) HPL-CM and MLA-CM produced inhibitory and stimulatory effects, respectively, on both basal and hCG-stimulated progesterone levels as well as on granulosa-luteal cell proliferation. These activities cannot be completely attributed to IL-2, and other mediators of leukocyte origin may, therefore, exist.

Cell Division↗
PubMed1997

Biphasic regulation of breast cancer cell growth by progesterone: role of the cyclin-dependent kinase inhibitors, p21 and p27(Kip1).

Depending on the tissue, progesterone is classified as a proliferative or a differentiative hormone. To explain this paradox, and to simplify analysis of its effects, we used a breast cancer cell line (T47D-YB) that constitutively expresses the B isoform of progesterone receptors. These cells are resistant to the proliferative effects of epidermal growth factor (EGF). Progesterone treatment accelerates T47D-YB cells through the first mitotic cell cycle, but arrests them in late G1 of the second cycle. This arrest is accompanied by decreased levels of cyclins D1, D3, and E, disappearance of cyclins A and B, and sequential induction of the cyclin-dependent kinase (cdk) inhibitors p21 and p27(Kip1). The retinoblastoma protein is hypophosphorylated and extensively down-regulated. The activity of the cell cycle-dependent protein kinase, cdk2, is regulated biphasically by progesterone: it increases initially, then decreases. This is consistent with the biphasic proliferative increase followed by arrest produced by one pulse of progesterone. A second treatment with progesterone cannot restart proliferation despite adequate levels of transcriptionally competent PR. Instead, a second progesterone dose delays the fall of p21 and enhances the rise of p27(Kip1), thereby intensifying the progesterone resistance in an autoinhibitory loop. However, during the progesterone-induced arrest, the cell cycling machinery is poised to restart. The first dose of progesterone increases the levels of EGF receptors and transiently sensitizes the cells to the proliferative effects of EGF. We conclude that progesterone is neither inherently proliferative nor antiproliferative, but that it is capable of stimulating or inhibiting cell growth depending on whether treatment is transient or continuous. We also suggest that the G1 arrest after progesterone treatment is accompanied by cellular changes that permit other, possibly tissue-specific, factors to influence the final proliferative or differentiative state.

Breast Neoplasms↗
PubMed1999

Progesterone stimulates pancreatic cell proliferation in vivo.

Treatment of cyclic and pregnant rats with progesterone stimulates cell proliferation within the islets of Langerhans. It was investigated whether this effect of progesterone depends on sex and/or the presence of the gonads or the presence of oestradiol. For this purpose, Silastic tubes containing progesterone were inserted s.c. in intact and gonadectomized male and female rats, and in gonadectomized female rats treated with oestradiol. After 6 days of progesterone treatment, rats were infused for 24 h with 5-bromo-2'-deoxyuridine (BrdU) and dividing cells were identified in pancreatic sections by immunostaining for BrdU. Progesterone treatment increased islet-cell proliferation in intact male and female rats (P < 0.05), but not in gonadectomized male and female rats or in gonadectomized female rats supplemented with oestradiol. Furthermore, in intact male and female rats, progesterone treatment also stimulated cell proliferation in extra-islet pancreatic tissue (P < 0.05). Identification of the proliferating cells, by double-immunocytochemistry, revealed that progesterone treatment stimulated proliferation of both alpha and beta cells within the pancreatic islets. In extra-islet pancreatic tissue, progesterone treatment stimulated proliferation in both duct (cytokeratin 20-immunoreactive) and non-duct cells. Progesterone treatment did not increase the number of single glucagon or insulin-containing cells outside the pancreatic islets, nor that of cytokeratin 20/insulin double-positive cells, suggesting that progesterone treatment did not stimulate differentiation of duct cells into endocrine cells. Progesterone treatment did not affect insulin responses to an i.v. glucose load (0.5 g/kg body weight). It is concluded that progesterone stimulates pancreatic cell proliferation indirectly; gonadal factor(s), not identical to oestradiol, is (are) probably involved.

20-alpha-Dihydroprogesterone↗
PubMed1983

Progesterone production in vitro by small and large ovine luteal cells.

Corpora lutea from cyclic ewes were dissociated by collagenase digestion and trypsin/EGTA treatment. Enriched fractions of endothelial cells, small luteal cells and large luteal cells were prepared on a stepped gradient of Ficoll 400. Progesterone was measured by radioimmunoassay and the results corrected so that progesterone production by each cell type could be determined. Endothelial cells did not produce significant amounts of progesterone, with or without LH stimulation, and endothelial cell contamination of small and large luteal cell fractions did not influence progesterone production by these fractions. Mean +/- s.e.m. basal progesterone production (n = 10) by large luteal cells was greater (P less than 0.001) on a per cell basis than that by small luteal cells (1.16 +/- 0.16 compared with 0.25 +/- 0.06 pg/h/cell). However LH, which stimulated a maximal 3-4-fold increase in progesterone production by small luteal cells (LH ED50 = 0.14 ng/ml), had no significant effect on production by large luteal cells, when contamination by small luteal cells was taken into account. The response of small luteal cells was specific to LH, other hormones having had no significant effect. Basal progesterone production by small luteal cells (0.12 +/- 0.03 fg/h/micron3) calculated per unit volume of cell was not significantly different from that of large luteal cells (0.17 +/- 0.02 fg/h/micron3). After LH stimulation, small luteal cells produced more progesterone than did large luteal cells (0.40 +/- 0.09 compared with 0.18 +/- 0.03 fg/h/micron3) (P less than 0.05). When the amounts of progesterone produced per cell were multiplied by the absolute numbers of large luteal (1 X 10(7] and small luteal (5 X 10(7] cells in the intact corpus luteum, basal progesterone production by large luteal cells (11.6 +/- 1.6 micrograms/h) was similar to that by small luteal cells (12.3 +/- 3.0 micrograms/h). However, under LH stimulation, progesterone production by the small luteal cell type (39.9 +/- 9.5 micrograms/h) was approximately 3 times greater than that by the large luteal cell type (12.3 +/- 1.6 micrograms/h) (P less than 0.05). We therefore conclude that small luteal cells may be the principal source of luteal progesterone production in the sheep.

Animals↗
PubMed1992

Role of progesterone and oestradiol in the regulation of uterine oxytocin receptors in ewes.

The interaction between oestrogen and progesterone in the regulation of the uterine oxytocin receptor in sheep was evaluated by measuring the binding of oxytocin to membrane preparations of caruncular and intercaruncular endometrium and myometrium. Ovariectomized ewes were assigned in groups of five to each cell of a 4 x 2 factorial design. The four treatments were (a) vehicle (maize oil) for 12 days, (b) progesterone (10 mg day-1) for 9 days, (c) progesterone for 9 days followed by maize oil until day 12 and (d) progesterone for 12 days. The two oestradiol treatments consisted of the administration of implants in the presence or absence of oestradiol. The ewes were killed on day 10 (group b) or day 13 (groups a, c and d) for collection of uterine tissues. The response of the caruncular and intercaruncular endometrium to the treatments was similar. In the absence of oestradiol, treatment with progesterone continuously for either 9 or 12 days reduced the concentration of the oxytocin receptor in comparison with both the control and the progesterone withdrawal group (in which values were similar). The presence of oestradiol reduced the receptor concentrations in control and both 9- and 12-day continuous progesterone treatment groups, but enhanced the concentration in the progesterone withdrawal group. The myometrial oxytocin receptors responded in a similar way to those in the endometrium to progesterone treatment alone, but the addition of oestradiol produced no further effect. In conclusion, progesterone and oestradiol caused downregulation of the endometrial oxytocin receptor. On the other hand, progesterone withdrawal, similar to that which occurs during luteolysis, increased receptor density in the presence of oestradiol. Progesterone may influence the response of the myometrium to oxytocin by causing a reduction in receptor density.

Animals↗
PubMed1998

Role of early luteal phase progesterone in control of the timing of the luteolytic signal in cows.

The effects of the pattern and concentration of early luteal phase progesterone on subsequent prostaglandin F2 alpha release in response to exogenous oxytocin was investigated during simulated luteal phases in ovariectomized cows treated with progesterone and oestradiol in patterns designed to simulate the range of luteal phase concentrations that occur naturally. In the first experiment, three groups of four cows received different concentrations of early luteal phase progesterone to determine the effective concentration in terms of cycle control. The results show that a plasma progesterone concentration early in the luteal phase as low as 0.6 ng ml-1 was sufficient to affect the timing of the subsequent luteolytic signal. In the second experiment, an early (day 1), a normal (day 4) or a late (day 7) postovulatory increase in progesterone was recreated in three groups of four cows. Responsiveness to oxytocin in the early progesterone group developed 3 days earlier than in the normal progesterone group, demonstrating the ability of early progesterone to advance the luteolytic signal. However, in the late progesterone group, there was no delay in the development of responsiveness to oxytocin compared with the normal progesterone group, demonstrating that the luteolytic signal is programmed to occur by a given time, irrespective of the early progesterone pattern. This demonstrates that a factor other than the timing of the early luteal phase progesterone increase ultimately must control the timing of luteolysis in cows.

Analysis of Variance↗
PubMed1980

Relative contributions of oestradiol and progesterone to the maintenance of sexual receptivity in mated female hamsters.

Sexual receptivity was measured as total lordosis duration (TLD) per 10 min test period with mating tests standardized across 24 h by giving the first test at the time when the lights were switched off (0 h) during a schedule of 14 h light : 10 h hardness and re-testing at intervals of 2 h. Long-term (14 days), high-level oestrogen treatment was necessary to achieve TLD scores similar to those found in female hamsters treated with oestrogen plus progesterone for 3 days. Mating of female animals treated with oestrogen only always resulted in a significant decrease in TLD scores at later tests (0 v. 2 h). If progesterone was given after the test at 0 h, a significant increase in TLD score was found at the test at 2 h and this increase was maintained across several tests. By 8 h TLD scores had decreased significantly in progesterone-treated mated female hamsters. Progesterone appeared to have, therefore, at least two roles in the regulation of sexual responsiveness in the female hamster: (a) under normal conditions of oestrogen exposure (1--3 days) progesterone was necessary for the induction of sexual receptivity and (b) progesterone was necessary for the maintenance of sexual responsiveness following short-term (10 min) mating in female hamsters treated with oestrogen only. In the oestrogen- and progesterone-treated female animal which is no longer receptive as a result of previous exposure to progesterone plus having been mated, sexual receptivity can be re-induced by treatment with a larger dose of progesterone. These findings have indicated that progesterone is the primary hormonal agent which regulates sexual receptivity in the mated female hamster. Furthermore, the eventual inhibitory effect of progesterone on sexual receptivity was not absolute even in the mated female animal but rather represent some form of habituation to that particular dosage of progesterone to which the animal had been previously exposed.

Animals↗
PubMed1981

Pharmacokinetics of progesterone in laying and non-laying hens (Gallus domesticus).

The metabolic clearance rate (MCR), volumes of distribution (Vd), production rate (PR) and half-life (t 1/2) of progesterone were measured in laying hens 8 h before, during and 8 h after the preovulatory surge of progesterone, and in non-laying hens (pullets and moulting hens) after a single injection of [1,2,6,7-3H]progesterone. A curve-fitting computer program showed that the data of [3H]progesterone metabolism best fit a two-compartment model. The MCR of non-laying birds (163.2 +/- 6.4 (S.E.M.) ml/min) was significantly greater than that of laying hens (122.4 +/- 6.1 ml/min). The mean PR of progesterone in laying hens measured 8 h before and 8 h after the preovulatory peak of progesterone (42.498 +/- 6.509 ng/min per kg 0.75) was comparable to that of moulting hens (61.771 +/- 14.363 ng/min per kg 0.75). However, the PR of progesterone in hens when measured during the preovulatory surge of progesterone (254.335 +/- 53.972 ng/min per kg 0.75) was significantly greater than 8 h before and 8 h after the surge. There were no significant differences among groups in the t 1/2 of the distribution phase (combined mean, 1.03 +/- 0.05 min), biologically active t 1/2 (combined mean, 10.93 +/- 0.31 min) or Vd of the central compartment (VdA; combined mean, 609.4 +/- 46.7 ml). However, the Vd in the peripheral compartment (VdB) was significantly greater in non-laying birds (combined mean, 3891.3 +/- 399.5 ml) compared with that of laying hens (combined mean, 2879.2 +/- 154.4 ml). There was no significant difference for MCR (ml/min( and PR (ng/min) of progesterone for non-laying pullets between methods using a single injection or continuous infusion. However, when body weight differences between the two groups of pullets were taken into account and the values adjusted by covariance analysis, the MCR obtained with the continuous infusion method was significantly (P less than 0.05) higher than the value obtained with the single injection method. It is concluded that (a) the preovulatory surge of progesterone is the result of an increase in the PR and not of a decrease in the MCR; (b) the lower MCR in laying hens compared with pullets and moulting hens is reflected by a smaller VdB, likely to be due to the presence of progesterone receptors of higher affinity and/or binding capacity in laying hens and to differences in extraction efficiency by progesterone-metabolizing organ systems; (c) t 1/2 in the hen would appear to be shorter than that reported for mammalian species. 24HD 12101

Animals↗
PubMed2001

Coeliac ganglion adrenergic activity modifies ovarian progesterone during pregnancy: its inter-relationship with LH.

Most of the fibres that constitute the superior ovarian nerve (SON) originate at the neuronal bodies of the coeliac ganglion and innervate rat ovarian stroma cells. The purpose of this work was to study the part played by innervation on ovarian release of progesterone on day 15 and at the end of pregnancy in an integrated in vitro system known as the coeliac ganglion-SON-ovary system. We also investigated, in the same system, whether there is some kind of inter-relationship between the effect of adrenergic agents and LH on progesterone release on day 15 of pregnancy. The coeliac ganglion and the ovary were incubated in separate compartments, linked by the SON. The ovary was immersed in 2 ml buffer solution (ovarian compartment) and the coeliac ganglion was immersed in 2 ml of a different buffer solution (ganglion compartment). Under these conditions, the accumulation of progesterone in the ovarian compartment medium was used as an endpoint. Conditions were standardised on day 15 of pregnancy, when the decrease in the release of ovarian progesterone caused by non-specific stimulation on the ganglion with KCl (56 mM) demonstrated the functional integrity of the system. Neural influence was evaluated by the addition of adrenergic agents at a concentration of 10(-6)M to the coeliac ganglion. On day 15 of pregnancy, noradrenaline and propranolol increased progesterone release while phentolamine diminished it. The existence of ganglionic tone was assessed by analysing progesterone basal levels at different stages of pregnancy. The highest secretion of progesterone was found to take place on day 15, diminishing as pregnancy advanced. In addition, adrenergic neural participation was studied during the physiological luteolysis occurring at the end of pregnancy. Major findings were that noradrenaline increased ovarian accumulation of progesterone on day 19 and decreased it on day 20, while propranolol and phentolamine diminished progesterone release on both days. In additional studies, some neuroendocrine aspects were investigated at a peripheral level. The addition of LH only to the ovarian compartment did not affect progesterone secretion. However, when LH in the ovarian compartment was accompanied by noradrenaline, propranolol or phentolamine in the ganglion compartment, the release of progesterone decreased. It can be concluded that modifications of the neural state of the coeliac ganglion affect ovarian progesterone secretion and the physiology of pregnancy via the SON. The results may confirm that the coeliac ganglion-SON-ovary system provides a direct link between the autonomic nervous system and physiological events during pregnancy.

Adrenergic Agents↗
PubMed1989

Effect of progesterone supplementation on pregnancy and embryo survival in ewes.

Two hundred eighteen ewes were used in experiments 1) to develop a progesterone supplementation regimen capable of sustaining serum concentrations of progesterone at about 2.0 ng/ml for a period of 50 d (Exp. 1) and 2) to determine the effects of progesterone supplementation (d 6 to 50 after mating) on pregnancy and embryo survival rates in mated ewes (Exp. 2). In ovariectomized ewes in Exp. 1, s.c. administration of four cylindrical (9.5 x 60 mm) silastic implants, containing 20% (1.1 g) progesterone by weight, sustained mean serum concentrations of progesterone of 1.9 +/- .07 ng/ml compared with 1.03 +/- .05 ng/ml in ewes bearing two implants. In Exp. 2 each ewe (n = 159) was mated to two fertile rams at a spontaneous estrus (d 0) during mid-breeding season. Mean ovulation rate, determined on a subgroup of 46 ewes, was 1.45 +/- .05. On d 6, ewes were assigned randomly to control (two implants containing no progesterone) or progesterone-treated (four implants similar to those used in Exp. 1) groups. From d 7 to 50 after mating, progesterone concentrations in serum were greater (P less than .001) in progesterone-treated (four implants similar to those used in Exp. 1) groups. From d 7 to 50 after mating, progesterone concentrations in serum were greater (P less than .001) in progesterone-treated (3.50 +/- .06) than in control (2.65 +/- .05) ewes. Pregnancy rates (86% and 83%) and calculated embryo survival rates (77% and 78%) were similar (P greater than .05) for the control and progesterone-treated groups, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

Continuous progesterone exposure associated with high contraction frequency in human term myometrial strips.

It has been shown that progesterone slightly reduced the work of human term myometrial strips. In vitro, 5 alpha-pregnane-3,20-dione and 3 alpha-hydroxy-5 alpha-pregnan-20-one, two major extra-hepatic metabolites of progesterone, had only minor effects or none at all. The myometrial strips were stored and superfused in a progestin-free buffer until the onset of contractions when progestin superfusion was commenced. In vivo, the human myometrium is never deprived of the influence of these steroids, either prior to or during labor. In the present investigation we studied whether progesterone and the two named progesterone metabolites would have a different effect when the myometrial strips were not deprived of steroid. Muscle biopsy samples from the lower uterine segment were immediately placed and stored in buffer containing progesterone, 5 alpha-pregnane-3,20-dione, or 3 alpha-hydroxy-5 alpha-pregnan-20-one. The strips were then bisected; one half was superfused with progestin buffer, and the other half with plain buffer to serve for control purposes. In strips continuously exposed to progesterone, the onset of contractions was delayed, compared with their progesterone-depleted controls. This was as expected, according to current opinion regarding progesterone and parturition. Once muscular contractions were established, the contraction frequency was significantly higher, due to a shorter muscular relaxation time, in the progesterone-superfused strips than in the controls and strips treated with progesterone metabolite superfusion. This was unexpected and can be interpreted as if continuous presence of progesterone facilitates human myometrial contraction frequency once contractions have started. Conversely, the 5 alpha-progesterone metabolites showed no effect or minor effects.

Adult↗
PubMedDate not supplied

The dosage of human chorionic gonadotropins influences the relationship between progesterone and cycle outcome during in vitro fertilization-embryo transfer.

OBJECTIVE: To determine if the dose of hCG affects the initial rise in progesterone seen in patients undergoing IVF-ET and therefore affects it usefulness as a predictor of cycle outcome. DESIGN: Comparison of the rise in progesterone with cycle outcomes for IVF patients receiving 5,000 or 10,000 mIU hCG to stimulate oocyte maturation. SETTING: University-based infertility program. Patients-One hundred six patients undergoing IVF-ET on a long protocol of down-regulation with GnRH, hMG stimulation, and hCG to stimulate oocyte maturation. Stimulation protocol varied only in dose of hCG [5,000 mIU (N = 72) vs. 10,000 mIU (N = 34)]. MAIN OUTCOME MEASURE(S): Rise in progesterone from 12 hours before to 12 hours after hCG administration and its relationship with cycle outcome. RESULTS: All 106 women exhibited a rise in progesterone following the administration of hCG. As seen in earlier studies, there appeared to be a relationship between minimal progesterone increases (<3-fold) and cycle failure in patients receiving 5,000 mIU (P < .02). However, using the criteria of the previous study, there appears to be no relationship between progesterone and cycle outcome in patients receiving 10,000 mIU (P = .30). Further, the higher dose of hCG appeared to induce greater increases in progesterone over the 24-hour period examined (P < .02). After readjustment of the critical value to 3.5-fold, there was an increased tendency toward cycle failure in women exhibiting a minimal progesterone increase. Unlike the relationship associated with 5,000 mIU hCG, though, the relationship between 10,000 mIU hCG and progesterone levels was not statistically different (P = .10). CONCLUSIONS: Increasing the dose of hCG used to stimulate oocyte maturity shifts the previously described relationship between progesterone and IVF-ET-cycle outcome. However, while it remains unclear if progesterone can be used as a predictor of outcome at the higher hCG dose, it appears clear that a relationship exists between minimal progesterone response to hCG and cycle failure.

Adult↗
PubMed2002

Sperm binding to the human zona pellucida and calcium influx in response to GnRH and progesterone.

In this study the effect of the sequential exposure of spermatozoa to progesterone and gonadotrophin-releasing hormone (GnRH) upon zona binding and the intracellular free Ca2+ concentration was evaluated. Sperm aliquots were treated as follows: (a) 0.7 micro mol l(-1) progesterone or 0.1% DMSO (progesterone solvent) followed by 50 nmol l(-1) of GnRH; (b) 50 nmol l(-1) of GnRH or distilled water (GnRH solvent) followed by 0.7 micro mol l(-1) of progesterone. Additional aliquots were incubated with DMSO or distilled water (controls) and with 0.7 micro mol l(-1) of progesterone or 50 nmol l(-1) of GnRH. All treatments were for 5 min. Motile spermatozoa were incubated in modified Tyrode's medium, at 37 degrees C, 5% CO2, 10 x 10(6) spermatozoa ml(-1), for 4.5 h. Intracellular Ca2+ concentration and sperm-zona binding was evaluated using fura 2 and the hemizona assay, respectively. GnRH and progesterone increased sperm-zona binding and the Ca2+ concentration. Regarding zona binding, the effect of GnRH was significantly greater when the spermatozoa had been previously treated with progesterone (progesterone-->GnRH=185 +/- 116 zona-bound spermatozoa versus DMSO-->GnRH=99 +/- 15, P < 0.001). On the other hand, previous treatment with GnRH did not modify their subsequent response to progesterone (GnRH-->progesterone= 114 +/- 19 zona-bound spermatozoa versus distilled water-->progesterone=108 +/- 22, NS). The results regarding intracellular Ca2+ showed a similar pattern. These findings suggest a priming effect of progesterone upon a GnRH-induced increase in sperm-zona binding and intracellular Ca2+.

Calcium↗