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At least 109 records · Page 6Linked to original sources
PubMed1989

Changes in ovarian steroidogenesis in vitro associated with final maturation of Atlantic croaker oocytes.

Changes in ovarian steroidogenesis during final oocyte maturation (FOM) in the Atlantic croaker (Micropogonias undulatus) were investigated in vitro by incubation of oocytes with tritiated pregnenolone, followed by chromatographic separation of the radioactive steroid products. Testosterone and estradiol-17 beta were the major tritiated steroids produced by the ovary before the onset of FOM. Induction of FOM by human chorionic gonadotropin, both in vivo and in vitro, coincided with the appearance of 17 alpha,20 beta,21-trihydroxy-4-pregnen-3-one (20 beta-S) as the predominant steroid product. The production of 17 alpha,20 beta-dihydroxy-4-pregnen-3-one and 11-deoxycorticosterone, maturation-inducing steroids previously proposed for other teleost species, could not be demonstrated in Atlantic croaker ovaries during FOM. The timely synthesis of 20 beta-S in croaker at the onset of oocyte maturation provides further evidence for a physiological role of 20 beta-S in the induction of FOM in this species.

17-Hydroxycorticosteroids↗
PubMed1989

In vitro ovulation, prostaglandin synthesis, and proteolysis in isolated ovarian components of yellow perch (Perca flavescens): effects of 17 alpha,20 beta-dihydroxy-4-pregnen-3-one and phorbol ester.

The present study investigated the effects of 17 alpha,20 beta-dihydroxy-4-pregnen-3-one (17,20 B-P) on (1) ovulation of isolated perch follicles in which the extrafollicular (EF) ovarian tissue had been removed; (2) prostaglandin F (PGF) and prostaglandin E (PGE) synthesis in EF tissue and intact (= follicles attached to EF tissue) and isolated follicles by radioimmunoassay and [14C]arachidonic acid incorporation; and (3) proteolysis in EF tissue and intact and isolated follicles by substrate sodium dodecyl sulfate-polyacrylamide gel electrophoresis. In addition, the ovulatory and proteolytic effects of the phorbol ester, phorbol-12-myristate-13-acetate (PMA), and the calcium ionophore A23187 on 17,20B-P-stimulated follicles were also studied in the presence/absence of indomethacin (IM) and nordihydroguaiaretic acid (NDGA). Ultrastructural analyses revealed that the preparation of isolated follicles also removed the surface epithelium of the follicle. While 17,20B-P stimulated ovulation and an increase in PGF and PGE in incubates of intact perch follicles, it did not in incubates of isolated follicles. In contrast, PMA, A23187, and a combination of PMA and A23187 stimulated ovulation of these isolated follicles. PMA/A23187-induced ovulation could be blocked by NDGA but not IM, and two hydroxyeicosatetraenoic acids (11- and 15-HETEs) were capable of partially reversing the NDGA block. Incorporations with [14C]arachidonic acid revealed that the EF tissue had a significant potential to produce PGF; however, 17,20B-P did not stimulate an increase in PGF or PGE (measured by RIA) in incubates of EF tissue alone. In addition, neither ovulation nor an increase in prostaglandins was observed in cocultures of isolated follicles and EF tissue. One major protease (66 kDa) was observed in the medium during incubation of intact and isolated perch follicles. No protease activity was present in incubates of EF tissue alone. Protease activity in 17,20B-P-stimulated incubates of intact tissue was significantly higher than in steroid-stimulated incubates of isolated follicles. Protease activity increased in the medium during incubation with PMA or a combination of PMA and A23187. This activity was blocked by NDGA but not IM. The NDGA block was partially reversed by 11-HETE. The combined results suggest that there is an interaction of EF tissue and follicle that is necessary, particularly for the stimulation of ovulation and prostaglandin production. Further, the results with phorbol esters and NDGA suggest that the follicular control of ovulation in perch may involve protein kinase C acting through the production of a lipoxygenase product.

17-Hydroxycorticosteroids↗
PubMed1990

Characterization of membrane receptor activity for 17 alpha, 20 beta, 21-trihydroxy-4-pregnen-3-one in ovaries of spotted seatrout (Cynoscion nebulosus).

The proposed maturation-inducing substance (MIS) of spotted seatrout (Cynoscion nebulosus) is 17 alpha, 20 beta, 21-trihydroxy-4-pregnen-3-one (20 beta-S). In this study, we characterized the binding of radioactive 20 beta-S to plasma membranes from the ovaries of spotted seatrout. Bound 20 beta-S was isolated by filtration of membrane suspensions and quantified by measurement of the radioactivity content of the filters. The saturable component of 20 beta-S binding reached equilibrium within 5 min at 0 degree, showed linearity with membrane concentration, and was pH dependent (optimum, 7.5-7.8). Scatchard analyses suggested a single class of high-affinity (KD, 10(-9) M), low-capacity (10(-13)-10(-12) mol/g ovary) binding sites for 20 beta-S. High levels of saturable binding were found in membrane preparations from the ovary, testis, and liver, but not from the gills. 17 alpha, 20 beta-Dihydroxy-4-pregnen-3-one (17 alpha, 20 beta-P) showed relatively little affinity for the 20 beta-S binding site. However, this steroid was converted to a compound immunologically and chromatographically similar to 20 beta-S by intact ovarian follicles, a finding which may explain its previously reported high potency in an in vitro oocyte maturation bioassay. Conversely, although reportedly a weak inducer of oocyte maturation, progesterone readily displaced 20 beta-S from its binding site. Thus, progesterone appears to be a relatively inactive ligand with high affinity for the 20 beta-S receptor. The concentration of 20 beta-S binding sites in ovaries was significantly higher during final oocyte maturation (germinal vesicle migration) than at earlier stages of development. These results strongly suggest that the 20 beta-S binding activity characterized in our study represents authentic MIS receptors. A distinct, soluble binding site for 17 alpha, 20 beta-P was also identified in seatrout ovaries, but its biological function remains unclear. A hypothesis is presented for the significance of this 17 alpha,20 beta-P binding site.

17-Hydroxycorticosteroids↗
PubMed1990

Identification of, and development of radioimmunoassays for 17 alpha, 21-dihydroxy-4-pregnene-3,20-dione and 3 alpha,17 alpha, 21-trihydroxy-5 beta-pregnan-20-one in the ovaries of mature plaice (Pleuronectes platessa).

Ovaries from a female plaice (Pleuronectes platessa) that had been injected with human chorionic gonadotrophin were incubated in vitro with 17 alpha-hydroxy[1,2,6,7-3H]progesterone. The major steroids produced by the ovaries were tentatively identified as 17 alpha,21-dihydroxy-4-pregnene-3,20di-one (11-deoxycortisol; 17,21-P), 17 alpha,21-dihydroxy-5 beta-pregnane-3,20-dione (3 alpha, 17,21-P-5 beta). A high proportion of these steroids was found in a conjugated form (sulphates or glucuronides). Radioimmunoassays were developed for 11-deoxycortisol and for 3 alpha,17,21-P-5 beta and were applied to fractions of mature male and female plaice plasmas and plaice ovarian incubates that had been separated on thin-layer chromatography. The presence of all three steroids, in vivo and in vitro, was confirmed. Particularly high amounts of conjugated 3 alpha,17,21-P-5 beta were found in the plasma of mature females (200-400 ng ml-1). The 3 alpha,17,21-P-5 beta radioimmunoassay also identified 3 alpha,17 alpha-dihydroxy-5 beta-pregnane-20-dione in all three fluids, despite the fact that this steroid was not among the radioactive incubation products of the ovary. These findings are compared with those from another flatfish, the dab (Limanda limanda), where the major gonadal steroids have been shown to be 17 alpha,20 alpha-dihydroxy-4-pregnen-3-one and its 5 beta-pregnane (3-keto and 3 beta-hydroxyl) metabolites.

17-Hydroxycorticosteroids↗
PubMed1990

Plasma levels of ovarian steroids, including 17 alpha,21-dihydroxy-4-pregnene-3,20-dione and 3 alpha,17 alpha,21-trihydroxy-5 beta-pregnan-20-one, in female plaice (Pleuronectes platessa) induced to mature with human chorionic gonadotrophin.

In one previous paper we reported on the identification of 11-deoxycortisol and 3 alpha,17 alpha,21-trihydroxy-5 beta-pregnan-20-one in the ovaries and plasma of mature female plaice and also described the development of radioimmunoassays for these two steroids. The present paper describes temporal changes in plasma levels of the free and conjugated forms of these and of some other steroids (17 alpha,20 beta-dihydroxy-4-pregnen-3-one, 17 alpha,20 beta,21-trihydroxy-4-pregnen-3-one, 17 alpha,20 alpha-dihydroxy-4-pregnen-3-one, 17 alpha-hydroxy-4-pregnen-3-one, testosterone, and 17 beta-oestradiol) in female plaice injected with and without human chorionic gonadotrophin (HCG). Oocyte final maturation, but not ovulation, was induced by HCG injections. Levels of most of the steroids were also elevated by the HCG injections and were significantly higher than in control fish throughout the experiment (112 hr). The two most abundant steroids were 11-deoxycortisol and 3 alpha,17 alpha,21-trihydroxy-5 beta-pregnan-20-one (up to 600 ng ml-1). Only relatively small amounts of 17 alpha-hydroxy-4-pregnen-3,20-dione (less than 15 ng ml-1), 17 alpha,20 beta-dihydroxy-4-pregnen-3-one, and 17 alpha,20 alpha-dihydroxy-4-pregnen-3-one (less than 5 ng ml-1) were found. 17 alpha,20 beta,21-Trihydroxy-4-pregnen-3-one was not present. Testosterone and 17 beta-oestradiol levels rose briefly, in response to the first of the two HCG injections, and then fell significantly. The ratio of conjugated to free steroids (except for 17 alpha-hydroxy-4-pregnene-3,20-dione and 17 beta-oestradiol) was almost always greater than 1. In the HCG-injected fish, there was a significant negative correlation between the response of 17 beta-oestradiol levels and the response of 11-deoxycortisol and 3 alpha,17 alpha,21-trihydroxy-5 beta-pregnan-20-one levels. This further confirms that, as teleosts approach the time of full maturity, there is switch-over in the ovaries from predominantly C19 and C18 steroid production to predominantly C21 steroid production.

17-Hydroxycorticosteroids↗
PubMed1992

In vitro biosynthesis of steroids, including 11-deoxycortisol and 5 alpha-pregnane-3 beta,7 alpha,17,20 beta-tetrol, by ovaries of the goldfish Carassius auratus during the stage of oocyte final maturation.

To examine the production of steroids with potential oocyte maturation-inducing or pheromonal activity in the goldfish (Carassius auratus) we have incubated mature ovaries of this species with 17-[3H]hydroxyprogesterone. The metabolites in the unconjugated, glucuronide, and sulfate fractions were identified by chromatography, microchemical reaction, and, in most cases, crystallization to constant specific activity. A major metabolite, present in all three fractions, was tentatively identified as 5 alpha-pregnane-3 beta,7 alpha,17,20 beta-tetrol. Although 17,20 beta-dihydroxy-4-pregnen-3-one (17,20 beta-P) was found in only low yield (as a sulfate), the presence of the tetrol indicates that it is synthesized in high yield but very rapidly metabolized. The relative proportions of 17,20 alpha-dihydroxy-4-pregnen-3-one (17,20 alpha-P), 11-deoxycortisol (17,21-dihydroxy-4-pregnen-3,20-dione) and 17,20 beta,21-trihydroxy-4-pregnen-3-one (17,20 beta,21-P) varied significantly between incubations and may be affected by the maturational state of the ovary or the method used to stimulate oocyte maturation. Testosterone was present predominantly as its glucuronide. Significant production of glucuronides and sulfates was observed in all incubations. Twenty-five to 30% of the radioactivity remained associated with the tissue, but the distribution of activity between the metabolites did not differ greatly from that found in the medium. These results indicate that 11-deoxycortisol and its 20 beta-reduced derivative (17,20 beta,21-P) may be significant in spawning female goldfish.

17-alpha-Hydroxyprogesterone↗
PubMed1988

Plasma 11-deoxycortisol and cortisol following dexamethasone in psychiatric patients.

As it has been suggested that calculating the ratio of cortisol to its biosynthetic precursor, 11-deoxycortisol, may enhance the sensitivity of the dexamethasone suppression test (DST) for depression, cortisol and 11-deoxycortisol were measured in 90 subjects undergoing this test. Among these subjects, post-dexamethasone cortisol and 11-deoxycortisol levels were significantly correlated (r = 0.65, P less than 0.001) and evaluating the ratio of cortisol to 11-deoxycortisol decreased rather than enhanced sensitivity of the DST.

17-Hydroxycorticosteroids↗