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PubMed1986

3 beta-Hydroxysteroid dehydrogenase in human placental microsomes and mitochondria: co-solubilization of androstene and pregnene activities.

3 beta-Hydroxysteroid dehydrogenase (3 beta-HSD) was solubilized from human term-placental microsomes and mitochondria using the non-ionic detergent, polyoxyethylene 20 cetyl ether (BrijR-58). Electron photomicrographs showed microsomes and mitochondria well disrupted by the detergent. The pregnene (C-21) and androstene (C-19) activities co-solubilized over a range (0.04-0.44) of BrijR-58/protein (B/P) concentration ratios (w/w). Optimal solubilization of the C-19 and C-21 activities were 63.3 +/- 2.6% (mean +/- SEM) from mitochondria (B/P ratio 0.37) and 71.8 +/- 2.1% from microsomes (B/P ratio 0.34). Detergent treatment of microsomes and mitochondria--varying time (5-90 min, pH 7.4) or varying pH (6.0-7.8, 90 min)--yielded C-19 activities identical with C-21 activities. The C-21/C-19 specific activity ratios of 3 beta-HSD in particulate, solubilized and chromatographed preparations were 2.28 +/- 0.16 (mean +/- SEM) for mitochondria and 1.97 +/- 0.07 for microsomes. 3 beta-HSD molecular weight estimates were 208,000 (microsomes) and 220,000 (mitochondria). These studies argue that a single protein is responsible for both the C-19 and C-21 activities of 3 beta-HSD and that this protein is the same in microsomes and mitochondria.

3-Hydroxysteroid Dehydrogenases↗
PubMed2001

Studies on Bacillus stearothermophilus. Part 1. Transformation of progesterone to a new metabolite 9,10-seco-4-pregnene-3,9,20-trione.

When Bacillus stearothermophilus, a thermophilic bacterium isolated from the Kuwaiti desert, was incubated with exogenous progesterone for 24 h, three monohydroxylated metabolites were produced. 20alpha-Hydroxyprogesterone was the major metabolite produced in 60.8 relative percentage yield. The other two monohydroxylated metabolites were identified as 6beta-hydroxyprogesterone and the rare 6alpha-hydroxyprogesterone in 21.0 and 13.6 relative percentage yields, respectively. A new metabolite 9,10-seco-4-pregnene-3,9,20-trione was isolated in 3.7 relative percentage yield. All metabolites were purified by preparative TLC and HPLC followed by their identification using 1H, 13C NMR and other spectroscopic data.

Biotransformation↗
PubMed1998

Synthesis and in vitro activity of some epimeric 20 alpha-hydroxy, 20-oxime and aziridine pregnene derivatives as inhibitors of human 17 alpha-hydroxylase/C17,20-lyase and 5 alpha-reductase.

Some epimeric 20-hydroxy, 20-oxime, 16 alpha, 17 alpha-, 17,20- and 20,21-aziridine derivatives of progesterone were synthesized and evaluated as inhibitors of human 17 alpha-hydroxylase/C17,20-lyase (P450(17) alpha) and 5 alpha-reductase (5 alpha-R). The reduction of 16-dehydropregenolone acetate (3a) was reinvestigated. NaBH4 in the presence of CeCl3 gave better stereo-selectivity for 20 beta-ol [20 alpha/20 beta-OH (4 alpha/4 beta) = 1/2.7] than LTBAH or the Meerwein-Pondroff method reported; reduction with Zn in HOAc formed exclusively 20 alpha-ol (4 alpha b). The 20 alpha- and 20 beta-hydroxy-4,16-pregnadien-3-one (9 alpha) and (9 beta) were synthesized from the alcohols 4 alpha b and 4 beta b. Several 20-oxime pregnadienes and 16 alpha, 17 alpha-, 17,20- and 20,21-aziridinyl-5-pregnene derivatives were also synthesized. LiAlH4 reduction of the 16-en-20-oxime (12b) yielded 20 (R)-(13a) and 20(S)-17 alpha,20-aziridine (13b) and 20(R)-17 beta,20-aziridine (14a). Several compounds inhibited the human P450(17) alpha with greater potency than ketoconzole. The 5 alpha-R enzyme assay showed that while (9 alpha) did not have any activity, (9 beta) and (3b) were potent 5 alpha-reductase (IC50 = 21 and 31 nM) inhibitors with activities similar to finasteride. The 20-oximes (17a) and (17b) were potent dual inhibitors for both 5 alpha-R (IC50 = 63 and 115 nM, compared to 33 nM for finasteride) and P450(17) alpha (IC50 = 43 and 25 nM, compared to 78 nM for ketoconazole).

5-alpha Reductase Inhibitors↗
PubMed1981

Inactivation of herpes simplex virus by a pregnene derivative (TX 3047).

1. Two strains of independently purified Herpes simplex virus type 1 were irreversibly inactivated after incubation with the pregnene derivative methyl-p-toluene sulphonate of diethylamino-3-beta-ethoxy-20-hydroxy-pregn-5-ene (TX 3047) in vitro. 2. RNA and DNA synthesis (both cellular and viral) were studied in the presence of TX 3047. Viral and cellular DNA synthesis but not viral RNA synthesis was reduced. 3. Formation of infectious particles was not affected by TX 3047 if the parental virus was absorbed to the cell before it was incubated with TX 3047. This suggests that TX 3047 acts at the level of the membrane.

Antiviral Agents↗
PubMed1983

Inhibition of steroidogenesis in cultured Leydig tumor cells by 22-amino-23,24-bisnor-5-cholen-3 beta-O1 and (20R) 20-phenyl-5-pregnene-3 beta,20-diol.

Using the cholesterol side-chain cleavage enzyme purified from bovine adrenals, we have previously shown that 22-amino-23,24-bisnor-5-cholen-3-beta-ol (22-ABC) and (20R) 20-phenyl-5-pregnene-3 beta, 20 diol (20-PPD) are potent competitive inhibitors of this enzyme. The studies presented herein were designed to characterize the effects of these new inhibitors on steroid production by intact cells. Using cultured Leydig tumor cells, we compared the effects of 22-ABC, 20-PPD, and aminoglutethimide (a well-known inhibitor of the cholesterol side-chain cleavage enzyme) on hormone-stimulated steroidogenesis. Our results show that these compounds inhibit steroid production in a dose-dependent manner and that 20-PPD and 22-ABC are about 100 and 4 times more active, respectively, than aminoglutethimide. In these cells, the inhibitory effects of the new compounds seem to be localized exclusively at the conversion of cholesterol to pregnenolone.

Aminoglutethimide↗
PubMed1977

[Attempt to induce, in the rat, a hepatitis of cirrhotic origin, using amino steroids: holaphyllaminol or amino 3-beta hydroxy-20-beta pregnene-5].

Holaphyllaminol, or Amino-3 beta-Hydroxy-20-beta Pregnene-5, was administered by gastric tube to male Wistar rats at dose of 50, 100 and 200 mg/kg/24 hr respectively, during 10, 20, 40 and 80 days. This substance provokes hepatic lesions beginning at the periportal region, the characteristics of which are a cholestasis, a canalar proliferation and a fibrosis. The interest of these alterations lies in the fact that they present the same features as certain human chronic hepatitis; their progression, a function of the dose of the toxin and the duration of treatment, may make possible to realisation of a model of experimental chronic hepatitis.

Animals↗
PubMed1983

Inhibition of adrenocortical cytochrome P-450scc by (20R)-20-phenyl-5-pregnene-3 beta,20-diol.

The effects of the cholesterol analogue, (20R)-20-phenyl-5-pregnene-3 beta,20-diol (20-PPD), on the catalytic and spectral properties of purified bovine adrenocortical cytochrome P-450scc were investigated. In contrast to results with cholesterol and (20R)-20-hydroxycholesterol, no conversion of 20-PPD to pregnenolone could be detected; instead, 20-PPD was found to be a potent inhibitor of cytochrome P-450scc. Kinetic analyses showed that the inhibition is reversible and competitive with respect to cholesterol with an apparent Ki = 30nM. Spectral binding studies with ferricytochrome P-450scc showed that 20-PPD formed a 1:1 complex with the enzyme, having an absorption spectrum similar to that produced by (20R)-20-hydroxycholesterol. These results indicate that 20-PPD binds with very high affinity to the substrate site on cytochrome P-450scc. The finding that the phenyl side chain is readily accommodated suggests the presence in this site of an open pocket which may be normally occupied by C-22 to C-27 of the cholesterol side chain.

Adrenal Cortex↗
PubMed2000

Plasma membrane receptors for the cancer-regulating progesterone metabolites, 5alpha-pregnane-3,20-dione and 3alpha-hydroxy-4-pregnen-20-one in MCF-7 breast cancer cells.

Recent observations indicate that the progesterone metabolite, 5alpha-pregnane-3,20-dione (5alphaP), which is produced at higher levels in tumorous breast tissue, promotes cell proliferation and detachment, whereas 3alpha-hydroxy-4-pregnen-20-one (3alphaHP), which is produced at higher levels in nontumorous breast tissue, suppresses proliferation and detachment of MCF-7 breast cancer cells. The objective of the current study was to determine the presence and characteristics of binding sites for these endogenous putative cancer-regulating steroid hormones. Radiolabeled 5alphaP and 3alphaHP were used in radioligand binding assays on MCF-7 cell (membrane, cytosolic, and nuclear) fractions. Binding of [(3)H]5alphaP and [(3)H]3alphaHP was observed only in the plasma membrane fraction, whereas estradiol binding sites were confirmed in the cytosolic and nuclear fractions. The respective membrane binding sites exhibited specificity for the 5alphaP and 3alphaHP ligands with no appreciable displacement at 200- to 500-fold excess by other steroids. The association rate constants were calculated as 0. 107/min and 0.0089/min and the dissociation rate constants were 0. 049 9 and 0.011 for 5alphaP and 3alphaHP, respectively. Saturation analyses indicated single classes of molecules with dissociation constants of 4.5 and 4.87 nM and receptor densities of 486 and 629 fmol/mg protein, respectively, for 5alphaP and 3alphaHP. Exposure of MCF-7 cells to estradiol for 1, 24, 48, and 72 h resulted in 2.3, 4. 2-, 2.99-, and 1.7-fold increases, respectively, in 5alphaP receptor density. 3alphaHP resulted in partial suppression of the estradiol-mediated increase in 5alphaP receptor density. This is the first report of receptors for the progesterone metabolites, 5alphaP and 3alphaHP, of their occurrence in breast cancer cell membranes, and of the induction of 5alphaP receptors by estradiol. The results provide further support for the potential importance of progesterone metabolites in breast cancer.

20-alpha-Dihydroprogesterone↗
PubMed1994

Involvement of an inhibitory G-protein in the signal transduction pathway of maturation-inducing hormone (17 alpha,20 beta-dihydroxy-4-pregnen-3-one) action in rainbow trout (Oncorhynchus mykiss) oocytes.

To investigate the mechanism by which the hormone 17 alpha,20 beta-dihydroxy-4-pregnen-3-one(17 alpha,20 beta-DP) acts on a receptor on the external surface of rainbow trout oocytes to induce maturation, the interaction between 17 alpha,20 beta-DP receptors and G-proteins was examined. Pertussis toxin (PT) catalyzed the ADP ribosylation of a 40-kDa protein in crude membranes from rainbow trout postvitellogenic oocytes, and cholera toxin (CT) labeled several proteins, including a major protein with an apparent molecular weight of 43 kDa. The 40-kDa protein was recognized by an antibody against the alpha subunit of inhibitory G-proteins (Gi), whereas the 43-kDa protein was recognized by an antibody against the alpha subunit of stimulatory G-proteins (Gs). Treating the membrane fraction with 17 alpha,20 beta-DP decreased the PT-catalyzed ADP ribosylation of the 40-kDa protein. In contrast, there was no significant change in the CT-catalyzed ribosylation of the 43-kDa protein after exposure to 17 alpha,20 beta-DP. The specific binding of 17 alpha,20 beta-DP to membrane fractions was decreased by PT. 17 alpha,20 beta-DP binding was also inhibited by nonhydrolyzable GTP analogs such as guanosine 5'-O-(3-thiotriphosphate) (GTP gamma S) and guanylylimidodiphosphate (GppNHp), but not by either ATP or guanosine 5'-O-(2-thiodiphosphate) (GDP beta S). Scatchard analysis revealed that GppNHp induced a 3.8-fold increase in the dissociation constant without a significant change in the number of binding sites, suggesting that the GppNHp-induced decrease in 17 alpha,20 beta-DP binding is due to the decrease in binding affinity between 17 alpha,20 beta-DP and its receptors. We conclude that the PT-sensitive Gi is involved in the signal transduction pathway of 17 alpha,20 beta-DP in rainbow trout oocytes.

Adenosine Diphosphate Ribose↗
PubMed1993

Steroidogenesis in Fundulus heteroclitus V.: purification, characterization, and metabolism of 17 alpha,20 beta-dihydroxy-4-pregnen-3-one by intact follicles and its role in oocyte maturation.

In vitro steroidogenesis of ovarian follicles incubated with radioactive precursors or a Fundulus heteroclitus pituitary extract (FPE) was investigated. Steroids were extracted from both the medium and follicular tissue and fractionated by liquid or thin-layer chromatography. A similar pattern of steroid metabolites was obtained with either [14C]pregnenolone or [14C]progesterone as exogenous precursor. Several metabolites comigrated with known reference steroids and thus were tentatively identified. Some have been previously reported to induce germinal vesicle breakdown (GVBD) in this and other species, particularly 17 alpha,20 beta-dihydroxy-4-pregnen-3-one (DHP). [3H]DHP added to intact follicles or denuded oocytes was also extensively metabolized. All the DHP metabolites produced by the intact follicle were tested for biological activity. Three of the metabolites were almost as effective inducers of GVBD as DHP itself, and two were tentatively identified as 5 alpha-pregnan-3 alpha,17 alpha,20 beta-triol and 5 alpha-pregnan-3 beta,17 alpha,20 beta-triol. However, DHP was the most potent and the quickest inducer of GVBD, indicating that its maturational action is not due to metabolic conversion to a more active form. In addition, we found two very active fractions after HPLC analysis of steroid extracts from FPE-stimulated follicles: one that corresponded to and was further identified (mass spectroscopy) as DHP and a second tentatively identified as the DHP metabolite 5 alpha-pregnan-3 beta,17 alpha,20 beta-triol. This study provides strong evidence that DHP plays the major role as a maturation inducing-steroid in F. heteroclitus, even though DHP is not the only active steroid produced by maturing follicles.

Animals↗
PubMed1996

Excretion of free and conjugated steroids in rainbow trout (Oncorhynchus mykiss): evidence for branchial excretion of the maturation-inducing steroid, 17,20 beta-dihydroxy-4-pregnen-3-one.

The goal of this study was to identify excretory routes of three main steroids produced by sexually mature male and female rainbow trout: 17,20 beta-dihydroxy-4-pregnen-3-one (17,20 beta-P), sulfated 17,20 beta-P (17,20 beta-P-S), and testosterone glucuronide (TG). Spermiating males or maturing trout were cannulated via the dorsal aorta and urinary bladder and injected with tritiated steroids. Blood, water, and urine were sampled over the next 12 hr when the fish were killed and bile was collected. The identities of the excreted products were determined by anion-exchange chromatography, reverse-phase high-performance liquid chromatography, enzyme hydrolysis, acid solvolysis, microchemical modification, and thin-layer chromatography. Following the injection of tritiated 17,20 beta-P, 25% of the radioactivity rapidly appeared unmodified in the water; 15% appeared slowly in the urine, mainly as 17,20 beta-P-S; and 40% was recovered in the bile, mainly as 17,20 beta-P-glucuronide. 17,20 beta-P was shown to be released into the water via the gills. Over the 12-hr sampling period, 20% of the 17,20 beta-P released into the water was taken up again by the fish (also branchially). A mathematical analysis showed that 40% of the 17,20 beta-P would have been released into the water in the absence of uptake. Following the injection of tritiated 17,20 beta-P-S, 63% appeared very rapidly, in an unmodified form, in the urine, and 15% was recovered in the bile. Following the injection of tritiated TG, 9% appeared slowly, mainly untransformed, in the urine, and 59% was recovered in the bile. These results show that the three types of steroids are released into the water by three different routes: free steroids, gills; sulfated steroids, urine; and glucuronidated steroids, bile.

Animals↗
PubMed1996

Effect of 17 beta-estradiol, testosterone, and 11-ketotestosterone on 17,20 beta-dihydroxy-4-pregnen-3-one production in the rainbow trout testis.

The principal hormone related to spermiation in Oncorhynchus mykiss is 17,20 beta-dihydroxy-4-pregnen-3-one (17,20 beta OHP). In the present study we analyzed the possible paracrine/autocrine effects of three other testicular steroids (17 beta-estradiol, 11-ketotestosterone, and testosterone) on the synthesis and secretion of this progestin in male rainbow trout. Pieces of testis at various stages of spermatogenesis were incubated for 24 or 48 hr with one of these steroids (5 to 800 ng ml-1) either alone or with the gonadotropin GtH II. Following incubation, 17,20 beta OHP was measured by RIA in the culture media. In vitro, only 17 beta-estradiol (E2) decreased 17,20 beta OHP secretion repeatedly and significantly when doses higher than or equal to 50 ng ml-1 were used. This effect was observed mainly at the spermiating stage and under gonadotropic stimulation. In turn, E2 did not seem to modify the testicular capacity to convert 17-hydroxyprogesterone into 17,20 beta OHP. In vivo, the circulating levels of E2 decreased at the beginning of spermiation, concomitantly with an increase of 17,20 beta OHP in plasma. These in vitro and in vivo data suggest a possible role for E2 in the regulation of 17,20 beta OHP secretion by testes, in particular during the spermiating period.

Animals↗
PubMed1997

Follicle and extrafollicular tissue interaction in 17alpha,20beta-dihydroxy-4-pregnen-3-one-stimulated ovulation and prostaglandin synthesis in the yellow perch (Perca flavescens) ovary.

Intact (attached to extrafollicular (EF) tissue) yellow perch follicles ovulate in vitro when stimulated with the steroid, 17alpha, 20beta-dihydroxy-4-pregnen-3-one (17,20-PG). However, follicles isolated from EF tissue will not ovulate under 17,20-PG stimulation. In the present study, the interaction of follicles and EF tissue in 17,20-PG-stimulated ovulation and prostaglandin synthesis was investigated by separating follicles from EF tissue at specific times during incubation. Following separation, the incubation of isolated follicles and EF tissue was continued. At 48 hr of incubation, isolated follicles were assayed for ovulation and the media of isolated follicle and EF tissue incubates were assayed by RIA for prostaglandin E (PGE) and prostaglandin F (PGF) levels. Steroid-stimulated follicles, isolated from EF tissue prior to 22 hr of incubation, ovulated less than 25%. However, there was a very large increase in the percentage ovulation in follicles separated from EF tissue from 24 to 32 hr. PGF levels increased significantly in 17,20-PG-stimulated follicles isolated from EF tissue after 22 hr. In contrast, mean PGE levels in steroid-stimulated follicle incubates appeared to be lower than control levels. Compared with controls, PGE and PGF levels were significantly lower in incubates of isolated EF tissue stimulated with 17,20-PG, and this did not appear to be related to the time of separation. The results demonstrate that follicles must interact with EF tissue for a specific length of time for ovulation and PGF synthesis to occur in isolated follicles. Further, the effects of 17,20-PG on prostaglandin synthesis appear to be specific for different tissue compartments.

Animals↗
PubMed1994

Stimulation of spawning behavior in castrated rainbow trout (Oncorhynchus mykiss) by 17 alpha,20 beta-dihydroxy-4-pregnen-3-one, but not by 11-ketoandrostenedione.

The onset of spawning behavior in male salmonids can be closely correlated to circulating levels of the progestin 17 alpha,20 beta-dihydroxy-4-pregnen-3-one (20-P). However, evidence that 20-P plays a causal role in the development and maintenance of spawning behavior in male salmonids is largely lacking. The purpose of this study was to investigate the effect of 20-P implants on the spawning behavior in castrated rainbow trout in the presence of a sexually active female. Mature rainbow trout were placed in five experimental groups: sham-operated and castrated implanted with either Silastic capsules containing 20-P, 11-ketoandrostenedione (11-KA), 11-KA + 20-P or empty capsules. Five to 6 weeks after implantation, all males were tested individually in a stream channel in the presence of a nesting ovulated female. Following behavioral observations, blood samples were taken from all tested males. Implants of 20-P and 11-KA resulted in increased plasma levels of 20-P and 11-ketotestosterone, respectively. Sham males exhibited the strongest behavioral response, both in the frequency of quiver bouts and attention toward the female. Castrated controls and 11-KA males showed no quiver response and reduced attention toward the female, while the behavioral responses shown by the 20-P and 20-P/11-KA males were intermediate. The results indicate that 20-P, but not 11-androgens, plays a significant role in the stimulation of spawning behavior in male rainbow trout.

Androstenes↗
PubMed1983

Characterization of a nonenzymatic component in the isomerization of 5-pregnene-3,20-dione catalyzed by human placental microsomes in vitro.

When human placental microsomes were heated in boiling water or exposed to trypsin, 30 to 40% of the 5-ene,3-ketosteroid isomerase activity was stable. Aqueous suspensions of chloroform:methanol extracts of microsomes also catalyzed isomerization of 5-pregnene-3,20-dione, activity being associated with the polar lipid fraction. The trypsin- and heat-stable activities, as well as that of resuspended microsomal lipids, showed a dependence on buffer composition and concentration. Little activity was detected in water at pH 7.0. Relative activities in various buffers were Hepes (4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid) greater than Pipes (1,4-piperazinediethanesulfonic acid) greater than potassium phosphate greater than Mes(4-morpholineethanesulfonic acid). The data suggest that the occurrence of membrane lipid-dependent nonenzymatic catalysis could contribute to the isotope exchange with solvent observed in previous studies of the mechanism of isomerization catalyzed by placental microsomes. The ability of the membrane lipid phase to catalyze steroid isomerization under certain conditions and the fact that this activity is subject to modifications by exogenous agents may have more general implications for an understanding of possible effects of xenobiotics on steroid hormone formation and action in vivo.

Buffers↗
PubMed1983

Plasma 17 alpha, 20 beta-dihydroxy-4-pregnen-3-one levels during sexual maturation of amago salmon (Oncorhynchus rhodurus): correlation with plasma gonadotropin and in vitro production by ovarian follicles.

Plasma gonadotropin (GtH) and 17 alpha, 20 beta-dihydroxy-4-pregnen-3-one (17 alpha, 20 beta-diOH-prog) levels were assessed by radioimmunoassay during the sexual maturation of female amago salmon (Oncorhynchus rhodurus). Both GtH and 17 alpha, 20 beta-diOHprog levels were low in vitellogenic females (June to September) and in those with full-grown immature oocytes and were elevated in mature and ovulated females to 40 ng/ml for GtH and 50-70 ng/ml for 17 alpha, 20 beta-diOHprog. In vitro production of 17 alpha, 20 beta-diOHprog by ovarian follicles and its stimulation by partially purified chinook salmon gonadotropin (SG-G100) was examined monthly using 18 hr incubations. In June and July, levels were too low to detect (less than 30 pg/ml) in media from all treatment groups. In August and September, SG-G100 at a concentration of 1 microgram/ml stimulated low levels of production (0.2-0.3 ng/ml). Full-grown, immature follicles in October showed a dose-response production of 17 alpha, 20 beta-diOHprog, averaging over 10 ng/ml when incubated with 1 microgram/ml SG-G100. Postovulatory follicles (1-2 days after ovulation) produced large amounts of 17 alpha, 20 beta-diOHprog, averaging over 100 ng/ml with 1 microgram/ml SG-G100. These results are discussed in relation to previous work on amago salmon and other species and together indicate that 17 alpha, 20 beta-diOHprog is the major steroid responsible for oocyte maturation in amago salmon, produced as the follicular mediator of gonadotropin.

Animals↗
PubMed1983

17 alpha,20 beta-dihydroxy-4-pregnen-3-one: plasma levels during sexual maturation and in vitro production by the testes of amago salmon (Oncorhynchus rhodurus) and rainbow trout (Salmo gairdneri).

The present study investigated seasonal changes in plasma 17 alpha,20 beta-dihydroxy-4-pregnen-3-one (17 alpha,20 beta-diOHprog) levels in precociously mature and fully grown mature male amago salmon (Oncorhynchus rhodurus) and in vitro 17 alpha,20 beta-diOHprog production by the testes of amago salmon and rainbow trout (Salmo gairdneri) in response to chum salmon gonadotropin. Plasma 17 alpha,20 beta-diOHprog levels were very low from June to September, and rapidly increased in October at the beginning of the spawning season in both precociously mature and fully grown mature male amago salmon. High levels of 17 alpha,20 beta-diOHprog were maintained during the period of active spermiation in precociously mature males, and quickly declined in mid-November. Incubation of testicular fragments from spermiating rainbow trout with chum salmon gonadotropin or 17 alpha-hydroxyprogesterone resulted in a highly significant increase in 17 alpha,20 beta-diOHprog levels in the incubation medium. The chum salmon gonadotropin was also effective in stimulating 17 alpha,20 beta-diOHprog production by testicular fragments obtained from amago salmon after the breeding season. These findings are discussed in relation to the possible involvement of 17 alpha,20 beta-diOHprog in spermiation of salmonids.

Animals↗
PubMed1983

Estradiol-17 beta and 17 alpha, 20 beta-dihydroxy-4-pregnen-3-one production by isolated ovarian follicles of amago salmon (Oncorhynchus rhodurus) in response to mammalian pituitary and placental hormones and salmon gonadotropin.

The effects of mammalian pituitary and placental hormones and dibutyryl cyclic AMP (cAMP) on the production of estradiol-17 beta and 17 alpha, 20 beta-dihydroxy-4-pregnen-3-one (17 alpha, 20 beta-diOHprog) by amago salmon (Oncorhynchus rhodurus) ovarian follicles in vitro were compared with partially purified chum salmon (Oncorhynchus keta) gonadotropin (SGA). Estradiol-17 beta production was examined using midvitellogenic ovarian follicles; SGA was the most effective hormone tested; at a dose of 1 microgram/ml it stimulated the production of approximately 4 ng/ml estradiol-17 beta. Ovine LH (o-LH) was about 0.5% as effective as SGA. Taking into account the relative purity of the preparations used, ovine FSH (o-FSH) was almost as effective as o-LH. Both HCG and bovine TSH (b-TSH) stimulated estradiol-17 beta production at high doses. Porcine ACTH (p-ACTH), ovine GH (o-GH), and ovine PRL (o-PRL) induced very modest increases in estradiol-17 beta; cAMP was highly effective. 17 alpha, 20 beta-DiOHprog production was examined using full-grown immature oocytes which were capable of maturing in vitro in response to 1 microgram/ml SGA. o-LH was about 0.5% as effective as SGA. o-FSH, b-TSH, and HCG appeared to be less effective in stimulating 17 alpha, 20 beta-diOHprog production, compared to estradiol-17 beta. o-GH and o-PRL induced marginal increases in production and p-ACTH had a very modest inverse dose-response effect.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenocorticotropic Hormone↗