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PubMed1975

Plasma hormones and pituitary luteinizing hormone in the rat during the early stages of pregnancy and after post-coital treatment with tamoxifen (ICI 46,474).

Plasma levels of oestradiol-17beta, progesterone and luteinizing hormone (LH) and pituitary levels of LH have been measured during the first 6 days of pregnancy, in normal rats and in rats receiving two doses of Tamoxifen (trans-1-(rho-beta dimethylamino-ethoxyphenyl)-1-2-diphenylbut-1-ene) on day 2 of pregnancy. In normal rats oestradiol rose strongly from early on day 3 to reach a peak concentration between 22.00 h on day 3 and 08.00 h on day 4. Progesterone concentrations rose from day 2 to reach peak values on day 3-4. In animals in which implantation was delayed 20-24 h by administration of Tamoxifen (0.1 mg/kg) orally on day 2 the increased level of plasma oestrogen was also delayed by 20 h. A higher dose of Tamoxifen (0.2 mg/kg) on day 2, which prevented implantation, completely eliminated the increase in plasma oestradiol. Neither dose of Tamoxifen affected the levels of progesterone. In both normal rats and rats treated with 0.1 mg Tamoxifen/kg, plasma LH levels declined by day 3 while pituitary levels rose steadily. There was no detectable change in either plasma or pituitary LH levels, accompanying the increase in plasma oestradiol in the normal rats. In animals receiving Tamoxifen (0.2 mg/kg), plasma LH increased to a maximum by day 4 while levels of pituitary LH decreased. The results show that the oestrogen "surge" of early pregnancy, occurs normally about midnight on day 3 and not late on day 4 as previously thought. It is considered that the plasma oestradiol peak in early pregnancy results from an increased release of FSH rather than an increased release of LH. Tamoxifen may owe part of its antifertility action to a capacity to inhibit the synthesis of oestradiol from progesterone.

Adrenalectomy↗
PubMed1976

Changes in brain, pituitary and uterine cytoplasmic oestrogen receptors induced by oestradiol-17beta in the ovariectomized rat.

The oestrogen specific, high-affinity cytosol receptor receptor (HAR) from amygdala, anterior, middle and posterior hypothalamus, pituitary and uterus was studied in the ovariectomized rat. A single in-vivo injection of oestradiol-17beta produced significant changes in both the tissue HAR concentrations and the apparent dissociation constants (Kd) determined in vitro. Four hours after oestradiol-17beta treatment (20 mug/kg), the HAR concentration was depleted in all tissues except the posterior hypothalamus. A lower dose of oestradiol-17beta (4 mug/kg) produced similar changes in HAR concentration with the exception of those in the amygdala and posterior hypothalamus. Twenty-four hours after oestradiol-17beta, HAR concentrations had returned to pre-injection levels in all tissues except the uterus. The uterine HAR concentrations were raised after both doses of oestradiol-17beta. The apparent tissue cytosol Kd values were decreased by both doses of oestradiol-17beta. The results suggest that brain, pituitary and uterine oestrogen cytosol HARs react to plasma oestrogen in a manner predictable by the steroid receptor hypothesis. The oestradiol-17beta-induced differential effects upon the tissue cytosol concentration may contribute to the overall spectrum of action of oestrogen in the central and peripheral reproductive processes.

Amygdala↗
PubMed1977

Steroid and prostaglandin concentrations in the plasma of pregnant ewes during infusion of adrenocorticotrophin or dexamethasone to intact or hypophysectomized foetuses.

Catheters were implanted into 16 ewes and their foetuses between days 110 and 124 of gestation. Hypophysectomy was attempted in eight of these foetuses. Continuous infusion of synthetic ACTH (10 microgram/h) or dexamethasone (1mg/24 h) into the foetus, starting between days 124 and 129, induced premature parturition. The concentration of progesterone in the maternal peripheral plasma decreased before parturition in all animals while the level of oestradiol increased in ewes with intact foetuses or in those in which hypophysectomy was incomplete. When hypophysectomy was complete, no increase in the maternal level of oestradiol occurred before delivery. The concentration of 13,14-dihydro-15-oxo-prostaglandin F2alpha increased in the peripheral plasma of ewes with intact or hypophysectomized foetuses infused with ACTH. It is suggested that an intact foetal pituitary gland is required for the rise in the level of oestrogen prepartum, but that this rise is not essential for increased prostaglandin production of parturition.

Adrenocorticotropic Hormone↗
PubMed1990

Buserelin. A review of its pharmacodynamic and pharmacokinetic properties, and clinical profile.

The gonadotrophin releasing hormone (GnRH) [luteinising hormone-releasing hormone (LHRH); gonadorelin] agonist buserelin is a promising new agent in the treatment of a variety of disorders in gynaecology and andrology, paediatrics and oncology. While a single dose of buserelin stimulates the release of pituitary gonadotrophins, multiple doses produce reversible pituitary desensitisation, and this specific blockade of gonadotrophin support to the gonads provides the basis for the drug's efficacy in conditions dependent on sex hormone secretion. Thus, buserelin provides comparable efficacy to orchidectomy or high dose estrogens in the treatment of hormone-sensitive prostate cancer and exhibits a lower incidence of adverse effects. During the early phase of treatment it may be particularly useful in combination with antiandrogens. Buserelin also appears promising in hormone-sensitive premenopausal breast cancer. Extensive studies have proven the value of buserelin in endometriosis, where it produces a transient remission with gradual recurrence of the disease on cessation of treatment. Surgical intervention is necessary in severe disease after buserelin-induced involution of the lesions. In patients with uterine leiomyoma, preliminary data suggest that buserelin may be beneficial in rendering surgery more conservative by reducing fibroid size, although it appears unlikely to preclude surgical intervention. The use of buserelin to induce a state of reversible hypogonadotrophism before administration of exogenous gonadotrophins is a promising strategy in the treatment of infertility associated with polycystic ovary syndrome and other conditions of infertility with underlying ovarian dysfunction; such a strategy also clearly enhances the efficiency of in vitro fertilisation programmes. Initial studies suggest its potential usefulness as a female contraceptive when administered intermittently in conjunction with a progestogen. Buserelin represents a first-line treatment of central precocious puberty. In endometriosis the adverse effect profile of buserelin is generally favourable, with hypoestrogenic effects such as hot flushes and vaginal dryness, and decreased libido, predominating. There is no apparent detrimental effect on lipid metabolism. The potential for adverse hypoestrogenic effects on bone mineral content with long term administration remains to be clarified. Thus, the GnRH agonist buserelin represents an advance in the treatment of a variety of gynaecological and andrological as well as paediatric and oncological conditions, infertility and other sex-hormone dependent conditions, with a low incidence of adverse treatment effects.

Animals↗
PubMed1977

Endometrial histology and circulating levels of medroxyprogesterone acetate (MPA), estradiol, FSH and LH in women with MPA induced amenorrhoea compared with women with secondary amenorrhoea.

Circulating levels of medroxyprogesterone acetate (MPA), estradiol, progesterone and gonadotropins were determined in 11 women on long-term treatment with depot-MPA (Depo-Provera DMPA) 150 mg i.m. every 12th week as a contraceptive. The women had amenorrhoea due to the treatment. Endometrial biopsy was performed one week after injection and at the end of the 12 week period. Blood samples were taken on the same occasions. The findings were compared with those in 12 untreated women having secondary amenorrhoea. MPA was still detectable in serum and the end of the 12 week period. Endometrial biopsies showed gestagenic effects in the second as well as in the first biopsy. No MPA was detectable in the untreated women with amenorrhoea, and no gestagenic effects could be demonstrated in their biopsies. The estradiol levels in the DMPA group were in the range of the early follicular phase of a normal menstrual cycle and showed a significant rise at the end of the 12 week period. On the last sampling occasion the estradiol levels did not differ from those in the untreated women with secondary amenorrhoea. The levels of progesterone and gonadotropins were in the range of the early follicular phase in both groups. These observations support that DMPA 150 mg i.m. every 12th week is a depotpreparation with prolonged effect, and inhibits ovulation and produces endometrial changes by means of biologically active serum concentrations throughout the 12 week period.

Adult↗
PubMed1978

Midtrimester intra-aminotic administration of prostaglandin F2alpha in combination with an hyperosmolar urea solution: effect upon plasma levels of estradiol, progesterone, and human placental lactogen (HPL).

A study was undertaken in order to investigate the clinical observation that patients who underwent midtrimester abortion using intra-amniotic PG F2alpha in combination with hyperosmolar urea, always aborted a dead fetus. Ten Caucasian primigravidae, aged between 16 and 22 years old and whose pregnancies ranged between 14 and 23 weeks in duration, were studied. The patients were randomly divided into two equal groups. The one group received urea and PG F2alpha intra-amniotically whereas the other received PG F2alpha alone. Blood was drawn for measurement of plasma estradiol, progesterone and human placental lactogen (HPL) prior to injection of the abortifacients and at regular intervals thereafter for a period of 120 min. The five patients who received the combination regime of treatment (urea + PG F2alpha) showed a rapid decline in the plasma concentrations of these hormones and induction of abortion was followed by fetal death within 35 min in all cases. In contrast, the five patients who received intra-amniotic PG F2alpha alone, did not (with a single exception), demonstrate this rapid decline in the plasma concentrations of the placental hormones measured. Also with the same single exception, these fetuses, although stillborn, were alive two hours after inducing abortion.

Abortion, Induced↗
PubMed1979

Uterine and ovarian estrogen receptor levels in climacteric women.

High affinity cytoplasmic estrogen receptors in the endometrium, myometrium and ovary of 15 climacteric women were studied. In addition, the concurrent serum estradiol and progesterone level of each woman was estimated and the endometrium examined histologically. The cytoplasmic estrogen receptor level of the endometrium and myometrium had remained extremely high in some cases several years after the menopause and in the presence of a completely atrophied endometrium. The lowest endometrial and myometrial estrogen receptor levels in pre-menopausal women were measured towards the end of the menstrual cycle. The eodometrial estrogen receptor level was roughly 2--3 times the comparable myometrial level. Estrogen receptors were also encountered in all cases in the cervical myometrium. The estrogen receptor levels of the ovary were low in all cases.

Adult↗
PubMed1992

Comparative contraceptive efficacy and mechanism of action of the norgestimate-containing triphasic oral contraceptive.

Norgestimate (NGM), a derivative of 19-nortestosterone with very specific affinity for the progesterone receptor, has been used in combination with ethinyl estradiol (EE) at low doses in both monophasic and triphasic oral contraceptives (OCs). An open-label comparative clinical trial was conducted with 4,234 healthy women using comparative clinical trial was conducted with 4,234 healthy women using triphasic levonorgestrel (LUG)/EE and NGM/EE through a total of 22,312 menstrual cycles. Contraceptive (LUG)/EE and NGM/EE through a total of 22,312 menstrual cycles. Contraceptive efficacy was excellent with both preparations, with no statistically significant between-regimen differences in pregnancy rates. The theoretical Pearl index was the NGM/EE triphasic, and 0.34 for the LNG/EE triphasic. Adverse experiences in groups were typical of those that may occur among women taking low-dose OC agents. was similar with the two preparations: 8.6% for the NGM/EE triphasic and 6.8% for the LNG/EE triphasic. In a separate mechanism of action study, specific endocrine parameters were investigated in 20 subjects using the NGM/EE triphasic for 4 cycles. Ovulation suppression was demonstrated in statistically significant decreases from pretreatment values in serum levels of luteinizing hormone, follicle-stimulating hormone, progesterone, and estradiol. Significant on-treatment increases in serum levels of sex hormone binding globulin evidenced minimal androgenicity. All hormonal values returned to or toward normal in the post-treatment cycle. The study results support those obtained in large noncomparative studies of the NGM/EE triphasic. This phased-dose combination suppresses ovulation and is a very effective, minimally androgenic contraceptive agent with a good safety profile.

Adolescent↗
PubMedDate not supplied

Seminal estrone, estrone sulfate, and estradiol-17 beta levels in fertile and infertile males.

The seminal levels of estrone (E1), estrone sulphate (E1S), and estradiol-17 beta (E2) were measured simultaneously after a chromatographic step in the semen samples of 79 men, including fertile volunteers, vasectomized subjects, and patients with oligozoospermia and secretory azoospermia. E1S concentrations in seminal plasma were higher than in serum (with a semen/serum ratio of approximately 2). Seminal E1 and E1S levels in oligozoospermic subjects were significantly decreased compared to controls (p less than 0.02 and p less than 0.03, respectively). The seminal E1S concentration was significantly reduced in azoospermic patients (p less than 0.02) and to a greater extent in vasectomized subjects (p less than 0.001). As seminal E1S is likely to be mainly of testicular origin, the decreased seminal E1S levels in oligoazoospermia are an index of impaired testicular function.

Estradiol↗
PubMed1976

Estrogen-binding parameters of cytoplasmic and nuclear receptors in an established rat endometrial cell line and tumor.

We have consistently found receptors for estradiol in both the cytosol and nuclear extracts of a rat endometrial cell line and in transplantable tumors derived from this cell line. The equilibrium dissociation constants (Kd) and the rate constants for the receptor-estradiol interaction in these cells and tumors did not differ significantly from those of the cytosol receptor in the rat uterus. A mean Kd of 3 x 10(-10) M with a rate of association (Ka) of 3 x 10(5) M-1sec-1 and a rate of dissociation (Kd) of 1.5 x 10(-5) sec-1 were obtained for nuclear and cytosol receptors for both tumors and cells. For uterine cytosol, a Kd of 8 x 10(-10) M, ka = 2.8 x 10(5) M-1sec-1 and kd = 1 x 10(-5) sec-1 were obtained. Although no differences were seen in equilibrium and kinetic parameters for estradiol-17beta binding between the nuclear and cytosol receptors of tumors and cells, an apparent difference in the relative affinities of nuclear and cytosol receptors for estrone was detected. This suggests that the binding site in nuclear receptors may have been modified. Implications of this observation with regard to receptor translocation and the mechanism of action of sex hormones are being considered.

Animals↗
PubMed1992

Hormone levels and anogenital swelling of female chimpanzees as a function of estrogen dosage in a combined oral contraceptive.

A combined oral contraceptive consisting of ethinyl estradiol (EE2) in three dosages (50, 100, and 400 micrograms) and norethindrone (0.5 mg) was given to female chimpanzees to determine the effect on endogenous sex hormone levels and anogenital swelling. Serum levels of EE2 increased with increasing dosages of EE2, estradiol decreased, and luteinizing hormone, progesterone and testosterone were maintained at approximately midfollicular phase levels. Urinary levels of EE2 glucuronide increased with the increasing dosages of EE2, whereas estrone and pregnanediol glucuronide were essentially undetectable. The cyclic increase in female anogenital swelling was abolished when the norethindrone was combined with 50 micrograms of EE2 and relatively constant and low levels of swelling were recorded. Relatively constant but successively higher levels of swelling were recorded when the norethindrone was combined with the higher dosages of EE2. These effects of oral contraceptives on female genital tissues are relevant to our laboratory studies of sexual behavior in chimpanzees given oral contraceptives and could also have implications for women taking oral contraceptives.

Anal Canal↗
PubMed1976

[Steroid receptors and hormonal receptivity. New pharmacological and therapeutic approaches applicable to the control of fertility].

The definition and main characteristics of the steroid hormone receptors are given. One may note a relationship between hormonal receptivity and the physiological changes in the concentration of the receptors in the target organs. The distribution of the various receptors is given in detail showing the existence of (a) different receptors for the same hormone in different target cells; (b) different receptors for different hormones in the same cells; (c) different receptors for the same hormone in the same cell. A new pharmacological approach is proposed based on differentiation of receptivities from which there results a dissociation of the therapeutic effects.

Drug Interactions↗
PubMed1975

Progesterone and estradiol patterns in women using an intrauterine contraceptive device.

Levels of progesterone, estradiol, LH, and FSH were measured in daily serum samples obtained from 4 subjects during a control cycle and during the first and fourth menstrual cycles after insertion of an intrauterine device (IUD). In addition, progesterone and estradiol were measured in serum samples obtained from 6 women 3, 4, or 5 months after IUD insertion, and from 6 women more than 1 year after IUD insertion. These measurements were compared to the data obtained from study of a large group of normal cycles. The results indicated that the IUD does not influence follicular maturation, time of ovulation, or corpus luteum function. The IUD did exert a local effect on the endometrium, causing the onset of menses to take place when steroid levels were higher than in control cycles.

Adult↗
PubMedDate not supplied

Radioimmunoassay of norethindrone (17 alpha-ethynyl-17 beta-hydroxy-4-estren-3-one) and ethynyl-estradiol (17 alpha-ethynyl-1,3,5, (10)-estratien-3, 17 beta-diol). Application to human plasma determination of norethindrone after oral administration of this steroid.

The experiment conditions for the evaluation of Norethindrone (17 alpha-Ethynyl-17 beta-hydroxy-4-estren-3-one, NET) and Ethynyl-estradiol (17 alpha-ethynyl-1, 3, 5 (10) estratrien-3, 17 beta-diol, EE) by radioimmunoassay are described. A minimal quantity of 25 pg of these two steroids could be evaluated using different reduced metabolites of NET, very little cross reaction is observed with 200 pg of these metabolites. No effect was observed with estradiol for the EE-antiserum. The NET-antiserum was used to evaluate this steroid and ethynodiol diacetate after oral administration to female volunteers. Maximal values in the plasma (2-3% of the administered dose) was found between 1-3 h after administration and at 24 h a concentration of 0.1-0.3% still remained in the plasma.

Administration, Oral↗
PubMedDate not supplied

[Steroidogenic function of the intra-arterial trophoblast in the rat. Ultrastructural, histoenzymologic and biochemical data].

The ultrastructural study of the intra-arterial trophoblast has revealed in the pregnant Rat a steroidogenic activity which has been confirmed by histoenzymologic observations (presence of delta 5-3 beta-HSDH and 17 beta-HSDH). At the 15th day postcoitum an in vitro investigation upon the metabolism of steroid hormone precursors suggests that the steroids (oestrogens, progestogens and androgens) secreted by the intra-arterial trophoblast have a local action upon the wall of the uterine placental arteries and are actively concerned with an important part upon the utero-placental hemodynamic as a whole.

Androstenedione↗