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At least 19 recordsLinked to original sources
PubMed1979

Ovarian responses of pregnant mare serum gonadotropin- and human chorionic gondotropin-primed rats: desensitizing, luteolytic, and ovulatory effects of a single dose of human chorionic gonadotropin.

We conducted a study to determine the morphological appearance and functional responsiveness of ovarian tissues after administration of hCG to 28-day-old rats primed 65 h earlier with PMS gonadotropin (PMSG) and after administration of a second dose of hCG 5 days later, i.e. to 33-day-old rats containing heavily luteinized ovaries. Sixty-five hours after the administration of 50 IU PMSG sc to 25-day-old rats, ovaries already contained an abundance of luteinized follicles and an adenylyl cyclase (AC) system that was responsive to LH, epinephrine, and NaF. The administration of 50 IU hCG sc at this time initially resulted in a loss of LH-responsive ovarian AC. Within 4 days of the hCG injection, the ovaries of the now 32-day-old rats were heavily luteinized, and ovarian AC was highly responsive to LH, epinephrine, and NaF. The administration of a single sc dose of 200 IU hCG to 33-day-old PMSC- and hCG-primed rats with luteinized ovaries resulted in a rapid desensitization of the ovarian AC to LH and a drop in serum progesterone levels, During the subsequent 7 days, serum progesterone levels continued to decline, while total ovarian AC reacquired responsiveness to LH by days 4--5 after the densensitizing dose of hCG. Dissection of ovarian components revealed, however, that the AC system of the corpora lutea originally present at the time of the second hCG injection remained permanently refractory to LH and that the AC in corpora lutea newly formed from freshly ovulated follicles exhibited a significant responsiveness to LH, epinephrine, and NaF. However, these new corpora lutea were not fully active, since serum progesterone never rose. Subcutaneous administration of 50 IU hCG to 33-day-old PMSG- and hCG-primed rats also promoted a rapid loss of AC responsiveness to LH. This lower concentration of hCG was not sufficient to promote follicular development or ovulation, and the ovarian AC remained refractory to LH for at least 7 days. Intravenous administration of 75 IU hCG to 33-day-old PMSG- and hCG-primed rats similarly promoted a rapid and permanent loss of luteal AC responsiveness to LH; again, follicles did not mature to a preovulatory state and, in fact, appeared to undergo atresia rather than ovulation. These results indicate that in heavily luteinized ovaries 1) hCG promotes desensitization of rat luteal AC to LH, 2) Desensitization of AC to LH stimulation in corpora lutea is permanent and irreversible, and 3) only under conditions where follicles mature and ovulate and new corpora lutea are formed does total ovarian AC reacqure responsiveness during the subsequent week.

Adenylyl Cyclases↗
PubMed1979

Influence of dose, repeated treatment and batch of hormone on ovarian response in heifers treated with PMSG.

The effect of two dose levels (1000 and 2000 i.u.) of three different commercially available batches of PMSG on the ovarian response (ovulations and follicles greater than 10 mn) of 42 heifers was examined in a randomized incomplete block experiment. Each animal was subjected to two consecutive but different treatments. A significant effect of dose was observed and there were fewer ovulations, but no reduction in the number of follicles, after the second PMSG treatment. There was no evidence that the ovarian response was affected by the PMSG batch used.

Animals↗
PubMed1975

Ovulation induction: ovarian response to human gonadotropins and synthetic gonadotropin-releasing hormone.

Human ovarian responses to FSH- and LH-releasing hormone (FSH/LH-RH) were observed at laparotomy and studies by histologic and histochemical examination of ovarian biopsy specimens. The responses were compared to those induced by human menopausal gonadotropin (HMG) and human chorionic gonadotropin (HCG) singly and together. The subjects were healthy, fertile, young women rendered anovulatory by injections of depomedroxyprogesterone acetate (DMPA) or depochlormadinone acetate (CA). Supplementary studies included measurement of urinary pregnanediol, examination of the cervix and vagina for estrogenic and progestational responses, and endometrial biopsy, Both HMG and HCG induced follicular growth and proliferation of granulosa and theca cells, but neither, when given alone, induced ovulation or corpus luteum formation. When given in conjunction they induced single or multiple ovulations and corpora lutea in 11 of 18 women treated. FSH/LH-RH CONSISTENTLY STIMULATED FOLLICULAR DEVELOPMENT AND INDUCED OVULATION IN 2 OF 16 WOMEN TREATED. Preovulatory mature follicles were found in 3 more. FSH/LH-RH may prove to be useful in the treatment of some cases of anovulatory sterility of hypothalamic origin.

Adult↗
PubMed1975

Ovarian response to exogenously administered human gonadotropins during the postpartum period.

Eighteen normal puerperal women received a combined administration of human menopausal gonadotropin (HMG) and human chorionic gonadotropin (HCG) and the ovarian response to these human gonadotropins was evaluated by the daily estimation of the 24 hour urinary excretion of total estrogens. Fourteen of the 18 subjects studied were responsive to the exogenously administered gonadotropins with a rise in the urinary estrogen excretion. Moreover, plasma follicle-stimulating hormone (FSH) and luteinizing hormone (LH) levels during the postpartum period were low compared to normal cycle gonadotropin levels. Thus, it might be concluded that puerperal anovulation and amenorrhea during lactation might be due to hypophyseal gonadotropic dysfunction rather than to ovarian refractoriness.

Amenorrhea↗
PubMed1978

Plasma prolactin levels and ovarian responsiveness to exogenous gonadotropins.

Standard gonadotropin stimulation tests of ovarian function and basal plasma prolactin measurements have been carried out in 151 patients with amenorrhea or severe oligomenorrhea. In 90 of these a standardized multiple pituitary stimulation test, including the prolactin response to thyrotropin releasing hormone, was also performed. There was a tendency for the basal estrogen excretion and the ovarian response to gonadotropin to be lower in patients with hyperprolactinemia. These correlations were weak and did not reach the levels of statistical significance except when compareing the ovariance response in patients with mild hyperprolactinemia to those with moderate or severe hyperprolactinemia. It is concluded that, in women, elevated plasma prolactin levels have little, if any, direct inhibitory influence on the ovariance response to gonadotropins in vivo.

Female↗
PubMed1979

Age-related changes in ovarian responsiveness to gonadotropins in normal and neonatally estrogenized mice.

Young ovariectomized mice were transplanted with ovaries obtained from either neonatally estrogenized or normal mice at different ages. Cyclic estrus ensued in 71% of the mice receiving ovarian grafts from 3-month-old normal donors. If donors were 12, 15 and 20 months old, cyclic estrus took place in 15, 10 and 0% of the recipients, respectively. By contrast, after transplantation of ovaries from neonatally estrogenized mice, and 3, 12 or 15 months, cyclic estrus occurred in about 42-48% of the recipients regardless of the age of donors. Three of 17 recipients receiving ovarian grafts from 20-month-old neonatally estrogenized donors still showed cyclic estrus. Therefore, in neonatally estrogenized mice, decline of ovarian responsiveness to circulating gonadotropins appears to be inhibited or delayed until at least 15 months of age.

Age Factors↗
PubMed1978

Oestrous and ovarian responses to exogenous progesterone and oestrogen in prepubertal ewe lambs in relation to the fecundity of their dams.

Oestrus was consistently induced by 20, 40 or 80 microgram oestradiol benzoate in progesterone-primed lambs aged 23 weeks and 17 weeks respectively in two experiments. The duration of oestrus increased linearly with increasing log dose of oestrogen, and was negatively correlated with the time of its onset. In the absence of progesterone there was a reduced incidence, later onset and shorter duration of oestrus. Progesterone alone did not induce oestrus. In lambs treated during January (Exp. 2), a later date of injection of oestrogen was associated with earlier onset and longer duration of oestrus. The induced oestrus was anovulatory. Oestrogen reduced the proportion of lambs with follicles greater than or equal to 3 mm in diameter whilst progesterone had no effect. Lambs which were the progeny of low- and high-fecundity dams did not differ in their oestrous or ovarian responses. Correlations between the dam's lamb production index and the time to onset and duration of the induced oestrus were also not significant.

Animals↗
PubMed1977

A study of the effects of bromocriptine on serum prolactin, follicle stimulating hormone and luteinizing hormone and on ovarian responsiveness to exogenous gonadotrophins in anovulatory women.

Twelve anovulatory patients with normal serum prolactin values and six with elevated values were treated with bromocriptine and the effects on serum prolactin, FSH and LH levels were recorded. Ovulation resulted in one patient who had normal prolactin values and in all six who had raised values. No patient with normal basal prolactin values showed an increase in serum FSH during therapy with bromocriptine, whereas 5 of the 6 patients with elevated values showed significant increases. Similar results were obtained for LH. Although these differences were highly significant (P less than 0-005) the majority of the serum FSH and LH values remained within the normal ranges. Five patients with normal basal prolactin values and one with elevated values were also treated with human pituitary gonadotrophin (HPG). An increase in ovarian responsiveness to HPG during therapy with bromocriptine was recorded in the one patient with initially elevated prolactin values. It was concluded that bromocriptine acts by allowing FSH to rise above threshold requirements for follicular stimulation.

Adult↗
PubMed1977

Pituitary and ovarian response to acute stimulation with LH-RH in normal and anovulatory women.

The LH FSH estradiol and progesterone responses to acute stimulation with LH-RH were studied in 12 normal women with ovulatory cycles (4 in the initial follicular phase, 4 in the mid-follicular phase and 4 in the late follicular phase) and in two castrated women, two under hormonal contraception, two with ovarian amenorrhea, twelve with central amenorrhea of no detectable origin (6 with normal and 6 with low basal gonadotrophins), eleven anovulatory patients with pseudomenstruation, two with anorexia nervosa, and two with pituitary amenorrhea. Each woman received a rapid i.v. injection of 100 microgram synthetic LH-RH at 9:00 a.m. Serum levels of LH, FSH, estradiol and progesterone were determined by radioimmunoassay in samples collected before and 60, 120, 240 and 480 minutes after injection. The findings were : 1) A significant rise in estradiol and progesterone levels, in addition to LH and FSH elevation, in normal women; 2) A lack of ovarian steroid response in the castrated women and in ovarian amenorrheas, which suggests that the source of steroid response to stimulation is not extragonadal; 3) Significant differences in the responses of the four hormones to LH-RH in the women with central amenorrhea in comparison with the normal group with great variability of results; the steroid response in the presence of a positive LH response might correlate with the severity and/or prognosis of the disorder, a point deserving further study; 4) In anovulatory women with pseudomenstruation, LH responses for the most part normal, and particularly, progesterone responses.

Adult↗
PubMed1976

Ovarian response to exogenous gonadotropins in women with elevated serum prolactin.

To determine if elevated serum prolactin hPRL inhibits ovarian steroidogenesis and contributes to the amenorrhea associated with galactorrhea syndromes, the following study was performed. Four women with amenorrhea, galactorrhea, and elevated serum hPRL levels were treated with menopausal gonadotropins (Pergonal) for the associated infertility. Urinary estrogen response was comparable to that in normal ovulatory women in each patient. Ovulation occurred in 3 of the 4 women with resultant conception and normal pregnancies. There was no evidence to support the contention that elevated hPRL interferes with ovarian function.

Amenorrhea↗
PubMed1979

Effect of modulators of cytoskeletal function on desensitization and recovery of PGE2-responsive ovarian adenylate cyclase.

Exposure of cultured Graafian follicles to PGE2 for 20 h resulted in a loss of the cyclic AMP response to fresh hormone. This desensitization was prevented by addition to the medium of D2O (25--50%) or Li+ (0.6--6 mM), agents believed to stabilize microtubules, as well as by phalloidin (1.0--10 microM), believed to stabilize the polymerized state of actin, in a dose-dependent manner. The spontaneous recovery of responsiveness to PGE2 upon incubation of refractory follicles for 6 h in hormone-free medium was prevented by addition to the medium of cytochalasin B (CB; 3 microgram/ml) or of the actin-binding myosin subfragment HMM S-1 (80 microgram/ml) or of anti-actin serum; viz. by agents likely to interfere with microfilament function. D2O (50%) caused morphological damage to the inner layer of the membrana granulosa and severe depression of protein synthesis. The other drugs used (phalloidin, LiCl and cytochalasin B) had no such effects. Resensitization of refractory follicles was also prevented by cycloheximide (10 micrograms/ml) and by actinomycin D (10 micrograms/ml). It is speculated that the recovery process may involve the insertion of a newly synthesized protein, such as PG-receptor, into the membrane by a mechanism dependent on microfilament action. These findings provide suggestive evidence for the hypothesis that cytoskeletal elements associated with the cell membrane take part in the modulation of the adenylate cyclase response to hormones.

Actins↗
PubMed1975

Pituitary and ovarian response patterns to stimulation in the postpartum and in galactorrhea-amenorrhea. The role of prolactin.

In order to assess the action of prolactin on the puerperal pituitary-ovarian resistance to physiologic stimulation, a study was conducted in 27 women divided into three groups. Group I: 9 postpartum women who did not wish to breastfeed their infants and received 2.5 mg bromocriptin (CB 154) twice daily for 14 days starting immediately after delivery; Group II: 9 normally lactating mothers; and Group III: 9 women with hyperprolactinemia associated with amenorrhea. The three groups underwent stimulation with LHRH and Pergonal 500. Results indicate lack of prolactin dependence in the pituitary-ovarian resistance of the puerperium. The possible mechanisms involved in the anovulatory period of lactation are discussed.

Adult↗
PubMed1978

Ovarian response in the estrual cat receiving varying dosages of HCG.

Laparoscopy was utilized to determine the ovulatory response of the domestic cat to various dosages of human chorionic gonadotropin (HCG) administered intramuscularly at one or two time periods during estrus. A linear HCG dose-ovulatory response was observed in queens receiving 0--500 IU HCG as a single injection on day 1 or as injections given on days 1 and 2 of estrus. Animals treated with 500 IU HCG on day 1 or days 1 and 2 of estrus produced the maximum percent ovulation rates based on pre- and post-HCG ovarian morphology observation by laparoscopy (100.0, 95.9%, respectively). A single injection of 500 IU HCG produced a significant increase (p less than 0.05) in mean percent ovulation rate in comparison to the 0, 50 and 100 IU HCG single injections. Administration of 500 and 250 IU HCG for 2 days of estrus resulted in a greater percent ovulation rate than the 2-day injection of 50 IU (p less than 0.05). These results indicate that the proportion of mature follicles ovulating in an induced ovulator, such as the cat, is an increasing function of graded dosages of exogenous hormone.

Animals↗
PubMed1979

Ovarian response to exogenous hormones in six-week-old lambs.

Crossbred lambs 5--6 weeks old were treated with human chorionic gonadotrophin (hCG) (500 or 1500 i.u.) alone, hCG plus pregnant mare serum gonadotrophin (PMSG) (1000 or 2000 i.u.), 1000 i.u. PMSG alone, or were untreated. PMSG alone and PMSG + hCG increased ovarian weight and uterine weight. PMSG alone stimulated growth and luteinization of follicles but PMSG + hCG induced ovulations and formation of corpora lutea. hCG alone did not change any of the characteristics which were measured. PMSG had a significant effect on the number of vesicular follicles but none of the treatments affected the number of growing follicles.

Animals↗
PubMed1979

Short-term regulation of LH and FSH secretion in cyclic women. III. Effects of varying doses of two consecutive LH-RH injections on pituitary and ovarian response.

The effects of two consecutive LH-RH injections at 120 min intervals with either a varying first or second LH-RH dose on pituitary gonadotrophin response were investigated in 15 eugonadal women to study pituitary secretory processes. Each volunteer underwent a total of 4 LH-RH double stimulation tests. In group I (n = 8) the first LH-RH dose of each of the 4 tests was fixed at 25 microgram, whereas the second LH-RH dose consisted of either 6, 25, 100 or 400 microgram. In group II (n = 7) the first LH-RH dose varied between 6 and 400 microgram, while the second LH-RH dose was kept constant at 25 microgram. Serum gonadotrophin and serum ovarian steroid levels were determined by radioimmunoassay before and after LH-RH administration. The volunteers in both groups served as their own controls. A linear log-dose response relationship was found between the various doses of LH-RH injected and the corresponding LH and FSH elevations elicited. However, the dose of the first LH-RH injection also significantly influenced the gonadotrophin reaction after the second LH-RH injection in a linear log-dose response relationship. Serum levels of oestradiol, 17-hydroxyprogesterone and progesterone significantly increased in response to the elevated serum gonadotrophin levels after LH-RH stimulation during the 4 h test period, but the rise did not correlate to the LH-RH dose used. The results indicate that LH-releasing hormone stimulates not only the release, but also the synthesis of LH and FSH in a dose-related manner. These findings are consistent with our previously reported concept that the magnitude of LH and FSH response to the first LH-RH injection reflects the "storage capacity", while the increase observed after the second LH-RH injection represents the "synthesis capacity" of the gonadotrophs.

Adult↗
PubMed1978

Ovarian responses and serum LH levels after retraction or removal of the oviduct in Japanese quail.

The effects of oviduct removal, oviduct displacement or sham-operation were studied in Japanese quail (Coturnix coturnix japonica). No significant differences were observed between the treatments for body weight, number of follicles larger than or equal to 6 mm diam., or number of ruptured follicles. Retraction or removal of the oviduct resulted in similar significant increases (P less than 0.05) in ovarian weight, diameter of the largest follicle, and serum LH levels when compared with the controls. Injection of yolk into normal hens did not cause any change. It is suggested that the oviduct normally exerts an inhibitory control on ovary growth without appreciable effect on ovulation rate.

Animals↗