酪氨酸对表面灌流系统中大鼠离体大,小黄体细胞孕酮生成的影响

参照我室Ｗａｎｇ Ｘｉａｏ－Ｎｉｎｇ的黄体细胞制备方法，制成大鼠黄体细胞悬浮液，经蔗糖密度梯度离心分离大，小黄体细胞，经６０ｍｉｎ预培灌后，每１０ｍｉｎ收集一次培灌液，用ＲＩＡ测定其中孕酮含量，实验结果表明，在培灌系统中，大黄体细胞的基础孕酮分泌量明显高于小黄体细胞，但小黄体地ｈＣＧ的敏感性强于大黄体细胞，不同剂量的酪氨酸对ｈＣＧ致大，小黄体细胞孕酮生成有不同程度的抑制，对小黄体细胞的抑制作用较为     

The effects of dehydroepiandrosterone (DHEA) and its metabolites on the polycystic ovarian condition (PCO): cystogenic changes of rat granulosa cells in vitro

During mammalian folliculogenesis, granulosa cells (GCs) are initially steroidogenically quiescent, later proliferate, and subsequently commence to hormonally differentiate, first producing estrogen and later, in the preovulatory stage, secreting both estrogen and progesterone. In this study and elsewhere, we have used follicle-stimulating hormone with a combination of growth factors in vitro to simulate the above in vivo conditions. In a previous study, we used dehydroepiandrosterone (DHEA) to accomplish the polycystic ovary condition (PCO) in rats. In the latter model, there were high circulating levels of DHEA and its metabolite, androstenedione. In the present study, we investigated the effects of high levels of DHEA (10⁻⁵M) and its metabolites, androstenedione, androstenediol and dehydroepiandrosterone sulfate on the quiescent, proliferative, and steroidogenically differentiating stages of GCs cultured in a serum-free medium for up to 10 days. In addition to possessing the regularly occurring organelles, when cultured with the aforementioned androgens, the GCs acquired endoplasmic reticulum of the smooth variety which is associated with steroidogenesis. The radioimmunoassay data showed that GCs cultured in the quiescent and proliferative stages in the presence of the androgens, no longer remain in these stages but proceed to differentiate in a preovulatory direction by producing both estrogen and progesterone. This study supports our hypothesis that high circulating levels of DHEA and/or its metabolites have most effect during the quiescent and proliferative stages of granulosa cells, with regard to their structure and their steroidogenic activities.     

Suppression of Anti-Candida Activity of Murine Neutrophils by Progesterone In Vitro: A Possible Mechanism in Pregnant Women's Vulnerability to Vaginal Candidiasis

Sex steroid hormones were examined for their effect on mycelial growth of Candida albicans, and the inhibitory activity of casein-induced murine peritoneal neutrophils against mycelial growth of C. albicans was examined in vitro using a crystal violet staining method or a [³H]glucose incorporation method. Four steroid hormones, danazol, estradiol, estriol and testosterone had no effect on mycelial growth of C. albicans, but progesterone appeared to convert the growth form of C. albicans from hyphal to yeast. Danazol (10^–6 m ) and progesterone (10^–5 m ) suppressed anti-Candida activity of neutrophils of non-treated mice, while testosterone, estradiol, and estriol did not. The anti-Candida activity of neutrophils of estradiol-pretreated mice was clearly suppressed by progesterone even at 10^–6 m which corresponded to its plasma concentration in pregnant women in the third trimester. The physiological significance of this suppressive effect of progesterone was discussed in relation to the vulnerability of pregnant women to vaginal candidiasis.     

Radioimmunoassay of serum medroxyprogesterone acetate (Provera) in women following oral and intravaginal administration.

A radioimmunoassay (RIA) method for measuring medroxyprogesterone acetate (MPA, Provera) in serum has been developed utilizing benzene:iso-octane extraction, 3H-MPA to assess procedural losses, goat anti-MPA-3-(0-carboxymethyl) oxime-bovine serum albumin serum and dextran-coated charcoal separation. Control serum blanks were undetectable, 200 pg/ml of MPA was measurable with a high reliability, and intra- and interassay coefficients of variation were 6 and 13 percent, respectively. MPA added to control serum was quantitatively recovered. Serum MPA levels measured in 2 women after ingestion of 10 mg MPA rose to 3.4 to 4.4 ng/ml within 1 to 4 hours after oral intake and fell rapidly thereafter to 0.3 to 0.6 ng/ml within 24 hours. Insertion of Silastic intra-vaginal rings (IVRs), containing 100 or 200 mg of MPA, into 4 women for periods of 3 weeks resulted in a rapid rise of serum MPA after insertion, rather stable MPA levels of 0.9 to 1.6 ng/ml while the IVRs were in place, and a rapid decline of serum MPA following IVR removal. Serum estradiol-17beta and progesterone concentrations, measured about 3 times a week in these patients, indicated that ovulation was consistently inhibited. The serum MPA levels observed in this study were approximately 5 times lower than those reported by other investigators using a double-antibody RIA of MPA in unextracted serum.     

Effect of essential fatty acid deficiency on G-proteins, cAMP-dependent protein kinase activity and mucin secretion in the rat submandibular salivary glands

Studies were conducted to determine whether β-adrenergic cell signalling is altered in submandibular salivary glands (SMSG) is essential fatty acid (EFA) deficiency. Three groups of rats were fed diets which were deficient in EFA (EFAD), marginally deficient in EFA (MEFAD) or contained sufficient amount of EFA (Control). Rats were killed after 20 wk on diets, SMSG were dissected out and cyclic AMP-dependent protein kinase (PKA) activity was measured. The specific enzyme activities were higher in the homogenates and supernatant fractions of the gland from EFAD and MEFAD rats compared with the controls. The relative levels of guanine nucleotide-binding regulatory proteins (Gs and Gi) were also measured in the SMSG membranes of rats fed the 3 diets. The levels of Gs were significantly higher in the EFAD and MEFAD groups than in the controls. No significant differences were observed in the secretion of trichloroacetic acid-phosphotungstic acid (TCA-PTA) precipitable glycoproteins from the SMSG slices among the 3 dietary groups.