OBJECTIVE To determine whether hyperinsulinism affects cytochrome P450c17 alpha activity by investigating the correlation between 17-hydroxyprogesterone (17-OHP) hyper-responsiveness to the gonadotropin-releasing hormone (GnRH) agonist, buserelin, and the insulin response to oral glucose in polycystic ovary syndrome (PCOS). DESIGN Ultrasound, clinical and hormonal parameters were used to defi...

I. E. Bush, C. L. Cope, A. Gowenlock, N. J. Holness, V. H. James, A. E. Kellie, C. J. 0. R. Morris, R. Neher, E. C. Osborn, R. V. Short, E. R. Smith, M. Stack-Dunne, J. F. Tait, S. A. S. Tait, M. Vogt and I. D. P. Wootton. Through the co-ordinated efforts of these scientists, the proceedings present a timely exposition of the current status of steroid chromatography on filter paper. Detailed co...

the correlation between serum steroid hormones, testosterone (t), 17β-estradiol (e2), and progesterone (p) and weight of female fishes, biological characteristics of gonad (e.g. fertilization rate, fluid egg rate, gonadosomatic index , polarization index and oocyte diameter) in 10 female of the migratory population of sterlet (acipenser ruthenus) and 5 female of the migratory population of sibe...

..A.LMOST ALL the neutral urinary 17-ketosteroids are conjugated with either sulfuric or glucuronic acids. These conjugates can be cleaved by strong acids at elevated temperatures (1), or by solvolysis in either ethyl acetate or tetrahydrohiran, each containing perchioric acid (2). Selective hydrolysis of steroid-glucuronosicles is achieved with $-glucuromi_ idase, although in some 1i1#{149}ill...

Ablation of androgen production through surgery is one strategy against prostate cancer, with the current focus placed on pharmaceutical intervention to restrict androgen synthesis selectively, an endeavor that could benefit from the enhanced understanding of enzymatic mechanisms that derives from characterization of key reaction intermediates. The multifunctional cytochrome P450 17A1 (CYP17A1)...

Evidence for nongenomic actions of steroids is now coming from a variety of fields of steroid research. Mechanisms of steroid action are being studied with regard to the membrane receptors and the activation of second messengers. The present study investigated the mechanism for the rapid effect of estrogen on acutely dissociated hippocampal CA1 neurons by using the whole-cell, voltage-clamp rec...

BACKGROUND In order to investigate whether gonadotrophin-releasing hormone (GnRH) antagonists exert a significant effect on steroid secretion in vivo compared with GnRH agonists, concentrations of sex steroid hormones (oestradiol, progesterone and testosterone) were studied in follicular fluid from women undergoing ovarian stimulation and treated with either GnRH agonist or antagonist. In addit...

Progestins used in contraception and hormone replacement therapy are synthetic compounds designed to mimic the actions of the natural hormone progesterone and are classed into four consecutive generations. The biological actions of progestins are primarily determined by their interactions with steroid receptors, and factors such as metabolism, pharmacokinetics, bioavailability and the regulatio...

Major rooibos flavonoids--dihydrochalcones, aspalathin and nothofagin, flavones--orientin and vitexin, and a flavonol, rutin, were investigated to determine their influence on the activity of adrenal steroidogenic enzymes, 3β-hydroxysteroid dehydrogenase (3βHSD2) and cytochrome P450 (P450) enzymes, P450 17α-hydroxylase/17,20-lyase (CYP17A1), P450 21-hydroxylase (CYP21A2) and P450 11β-hydroxylas...

Well-established associations between reproductive characteristics and epithelial ovarian cancer (EOC) support an involvement of sex steroid hormones in the etiology of EOC. Limited previous studies have evaluated circulating androgens and the risk of EOC, and estrogens and progesterone have been investigated in only one of the previous studies. Furthermore, there is little data on potential he...