In vivo Regulation of Prolactin Gene Expression in the Male Rat: Role of Sex Steroids and Dopamine

The influence of sex steroids and the dopaminergic system on the in vivo modulation of prolactin (PRL) mRNA levels was investigated by quantitative in situ hybridization in the male rat anterior pituitary gland. In situ hybridization was performed using a [³⁵S]-labeled cDNA probe encoding PRL. Orchiectomy performed 14 days earlier did not modify PRL mRNA levels. In orchiectomized rats treatment with the dopaminergic agonist bromocriptine for 14 days decreased PRL mRNA levels by 30%, while in intact animals the same treatment did not induce any changes in PRL mRNA levels. Administration of the dopamine D₂ receptor antagonist haloperidol in both intact and orchiectomized rats induced a 4-fold increase in mRNA levels. Administration of dihydrotestosterone to orchiectomized animals which had been treated or not with haloperidol or bromocriptine did not modify PRL mRNA levels. In orchiectomized animals administration of 17ß-estradiol (0.25 μg twice daily) for 14 days caused a 4-fold increase in amounts of PRL mRNA. Administration of bromocriptine to 17ß-estradiol-treated animals induced a 15% decrease of PRL mRNA levels compared to those obtained by 17ß-estradiol administered alone. The concomitant administration of 17ß-estradiol and haloperidol resulted in a 50% increase in PRL mRNA levels compared to those measured in animals treated with haloperidol alone. The present results clearly demonstrate that in vivo estrogen as well as dopamine-mediated mechanisms play a regulatory role in PRL mRNA levels in the male rat.     

溃疡病男性患者血浆睾丸酮和雌二醇浓度的变化

本文对20例溃疡病男性患者和20名男性健康者进行了血浆睾丸酮和雌二醇则定。两者相比,溃疡病男性患者血浆睾丸酮水平虽较健康者为高,但经统计学处理,无显著差异(t:1.616 P>0.05);而血浆雌二醇水平,溃疡病男性患者低于健康者,经统计学处理,有显著差异(t:2.53 P<0.05)。     

女性银屑病患者血清性激素浓度测定

对20例女性、非妊娠期、生育年龄的寻常型、进行期银屑病患者检测了雌二醇(E_2)、孕酮(P)和睾酮(T)的血清浓度。结果为:卵泡期E_2平均值为84±61.6pg/ml,黄体期E_2平均值为164.9±115pg/ml,均显著高于正常平均值(P值分别为<0.001,<0.005);黄体期P平均值为2.67±4.62ng/ml,显著低于正常平均值(P<0.005);T平均值在正常范围,提示银屑病可能与血清E_2和P浓度有关。     

Prodrugs for Improved Oral β-Estradiol Bioavailability

Prodrugs of -estradiol (1) were prepared with the objective of improving its oral bioavailability. -Estradiol-3-acetylsalicylate (2), -estradiol-3-salicylate (3), and -estradiol-3-anthranilate (4) were synthesized. With these prodrugs the 3-phenolic hydroxy group of estradiol was protected, so that first-pass conjugative metabolism could be reduced. Prodrug hydrolysis rates in dog and human plasma in vitro were determined. Deacetylation of estradiol-3-acetylsalicylate was much more rapid than its hydrolysis to estradiol. In dogs, oral estradiol bioavailability after administration of 2 and 4 was 17-fold and 5-fold higher, respectively, than after oral 1.     

Transdermal Dual-Controlled Delivery of Contraceptive Drugs: Formulation Development,in Vitro and in Vivo Evaluations,and Clinical Performance

Several transdermal contraceptive device (TCD) formulations were developed to provide a dual-controlled transdermal delivery of levonorgestrel (LN), a potent progestin, and 17-estradiol (E₂), a natural estrogen. Using a sensitive HPLC method, the in vitro release and skin permeation profiles of LN and E₂ from various TCD formulations were simultaneously characterized in the hydrodynamically well-calibrated Valia–Chien skin permeation cells and both were found to follow zero-order kinetics. The rates of drug release and skin permeation were observed to vary significantly depending upon some formulation parameters. Six-month stability studies were performed on seven formulations at room and elevated temperatures (37 and 45°C), and two (Formulations 4 and 5) were found to be acceptable, based on drug recovery, release rate, and skin permeation rate data. Judging from the 6-month accelerated stability studies, it is projected these two formulations will have shelf-life of at least 2 years. As a result of development of an efficient manufacturing process, Formulation 4 was selected for further evaluation. One-week primary skin irritation evaluation in 6 rabbits indicated that Formulation 4 is nonirritating, and it was thus selected for Phase I clinical bioavailability/dose proportionality studies in 12 healthy female volunteers of child-bearing age. Results of pharmacokinetic and pharmacodynamic analyses demonstrated that it is capable of achieving and maintaining a steady-state serum level of LN throughout the 3-week treatment period by weekly applications of one or two TCD patches (10 or 20 cm²). A dose proportionality was obtained in the serum drug levels, daily dose delivered, and contraception efficacy. An excellent correlation was obtained for the rates of transdermal delivery determined by the in vitro studies using human cadaver skin, the in vivo studies in rabbits, and the clinical studies in living subjects.     

Ethinyl estradiol treats collagen-induced arthritis in DBA/1LacJ mice by inhibiting the production of TNF-alpha and IL-1beta

We previously demonstrated the therapeutic effects of ethinyl estradiol (EE), an orally active estrogen and a component of birth control pills, in encephalitogenic autoimmune encephalomyelitis (EAE). In this study, we report the effectiveness of EE in treating collagen-induced arthritis (CIA) induced with bovine type II collagen (bCII) in DBA/1LacJ mice, a CIA susceptible strain. Both low and high doses of EE notably suppressed clinical and histological signs of CIA in a dose-dependent manner compared to vehicle-treated controls. Oral treatment with EE decreased proliferation and secretion of pro-inflammatory factors, TNF-alpha IFN-gamma, MCP-1 and IL-6 by bCII peptide-specific T cells, production of bCII-specific IgG2a antibodies, and mRNA for cytokines, chemokines and chemokine receptors in joint tissue. This is the first report demonstrating effective treatment of joint inflammation and clinical signs of CIA with orally administered ethinyl estradiol, thus supporting its possible clinical use for treating rheumatoid arthritis in humans.     

Estrogenic activity of estradiol and its metabolites in the ER-CALUX assay with human T47D breast cells

A number of metabolites of 17beta-estradiol were tested for their estrogenic activity using the ER-CA-LUX assay based on the increased expression of luciferase in exposed T47D breast cancer cells. E2beta and estrone showed similar potencies in the test, whereas E2alpha was 100 times less active. Incubation of cells with estrone (0.35 microM) resulted in the formation of E2beta, whereas the reverse reaction was observed for E2beta. The resulting equilibrium may explain the similar estrogenic potency of estrone in the test. The synthetic 17-hydroxy benzoate ester of E2beta was 3 times less active than the parent compound. The 17-hydroxy palmitate and oleate esters of E2beta, were respectively 25 and 200 times less active than the parent compound. The 2-hydroxy metabolites of E2beta and estrone showed a 5,000 to 10,000 fold lower activity. The 4-hydroxy metabolites were more potent than the 2-hydroxy metabolites, showing only a 20-200 times lower activity. The 2- and 4-methoxyesters of estrone were 700 times less active. It is concluded that the estrogenic potency of metabolites formed in cattle after treatment with E2beta, like estrone, E2alpha and especially the esters of E2beta, may be significant with respect to the potential risk of the use of estradiol for growth promotion in domestic animals in certain countries.     

Hormonal contraception without estrogens

The long-term clinical effects of ethinyl estradiol and the impact on environmental safety of the alkylated estrogen components used in combined contraceptive pills remain the subject of debate. The development of improved methods for the use of progestogen-only contraception would represent a viable and desirable option. Several progestogen compounds are not alkylated, and these can be delivered through a variety of routes. Some of the progestogen-only methods are well established in clinical use. Estimates for both perfect and typical effectiveness are less than one pregnancy per 100 woman-years with oral, injectable, implantable and intrauterine methods. In practice, with the oral progestogen-only method, perfect and typical effectiveness range from three to five pregnancies per 100 woman-years. The main side effect with all progestogen-only methods is unpredictable vaginal bleeding during the first months of use, and this may lead to discontinuation. Nevertheless, continuation of use is more frequent if patients are well informed of this side effect before treatment begins. No cardiovascular- and cancer-related side effects have been proven.     

Anti-Müllerian hormone concentrations in maternal serum during pregnancy

BACKGROUND: In females, anti-Müllerian hormone (AMH) is expressed only by the ovary. AMH is secreted by the granulosa cells of ovarian follicles and appears to regulate early follicle development. AMH is detected in serum from women of reproductive age and its levels vary slightly with the menstrual cycle, reaching the peak value in the late follicular phase. This study investigated serum AMH levels throughout gestation and after delivery in healthy pregnant women. METHODS: This cross-sectional study recruited pregnant women and healthy non-pregnant women, 84 in total. AMH, FSH and E2 were measured in the follicular phase, in the three trimesters of pregnancy and in early puerperium. RESULTS: Estradiol and FSH levels followed the expected patterns during gestation. During the follicular phase of the menstrual cycle AMH levels were 1.9 +/- 0.5 ng/ml. In the three trimesters of pregnancy and in early puerperium AMH levels were: 2.1 +/- 0.56, 2.4 +/- 0.64, 1.95 +/- 0.6 and 2.05 +/- 0.55 ng/ml respectively. No significant modifications were found in AMH levels during pregnancy and in the early puerperium. CONCLUSIONS: This study has obtained information on AMH and on the possible relationship with FSH. We hypothesize that the profile of the new marker of ovarian activity AMH may indicate that initial non-cyclic ovarian follicular activity during pregnancy is not abolished. Moreover FSH, does not seem to play a direct role on AMH synthesis and secretion.     

Long-term effects of transdermal and oral estrogens on serum lipids and lipoproteins in postmenopausal women

The transdermal and oral administration of estrogens for one year were compared with respect to the effects on lipid metabolism. Eighty-one postmenopausal women (1.5-3 years after menopause) were randomly divided into three groups. The first two groups received sequential estrogen treatment with either transdermal estradiol (Estraderm TTS, Ciba Geigy; 50 μg/day; 24 women) or 0.625 mg/day conjugated estrogens (Premarin, Wyeth; 20 subjects), respectively. In both groups medroxyprogesterone (10 mg/day per os) was added for 12 days of each cycle. Thirty-five subjects served as control group without therapy. No significant changes in the lipid profile was observed in control subjects after 1 year of follow-up. Serum triglycerides decreased significantly (-10.9 ± 26% S.D.; P < 0.05) in transdermal treated women, whereas it slightly rose in oral estrogen group. Comparable significant decreases in total and low density lipoprotein (LDL) cholesterol (mean range -6.5/-18.0%) were observed in women on estrogen replacement therapy. High density lipoprotein (HDL) cholesterol significantly diminished in transdermal estradiol group, but it rose slightly in the oral estrogen group. Thus the fraction of HDL cholesterol over LDL cholesterol did not change in the transdermal group whereas it significantly rose in subjects treated with oral estrogens. It remains to be established to what extent these differences on lipid metabolism are relevant for the prevention of cardiovascular diseases.