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Query: UMLS:C0338671 (Steroids)
 9,479 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Androgen receptors have been found in duck preen glands by using dextran-coated charcoal adsorption. They bound DHT with high affinity (KD = 0.2 nM), limited capacity (45 fmoles/mgP) and good specificity. They sedimented at 8 S in a sucrose gradient and were destroyed by pronase digestion and heating. An estrogen receptor having different binding specificity was also demonstrated. On the basis of a marked annual cycle of gonadal activity in ducks, this system appears appropriate for studying the regulation of sex steroid hormone receptors.
Steroids 1977 Nov
PMID:Evidence of androgen and estrogen receptors in the preen gland of male ducks. 61 36

Spermatozoa from bovine ejaculates and cauda epiditymidis were incubated with either tritiated 17 beta-hydroxy-5 alpha-androstane-3-one (DHT) or 5 alpha-androstane-3 alpha, 17 beta-diol (3 alpha-diol). Examination of the medium incubations demonstrated metabolic conversion of both DHT and 3 alpha-diol when these steriods were incubated with ejaculated sperm. In addition to this interconversion, the following metabolities were identified: 5 alpha-androstane-3 beta, 17 beta-diol, (3 beta-diol), androsterone and 5 alpha-androstane-3, 17-dione (5 alpha-A-dione). Incubations with cauda spermatozoa showed similar metabolic patterns. Androgen binding was exhibited by both sperm types. Examination of the washed cauda sperm pellet, following incubations with 3 alpha-diol showed that the incubated steroid was the most abundantly bound. DHT and 5 alpha-androst-16-en-3 alpha-ol (delta 16-3 alpha-ol1 were also detected. The major part of the radioactivity bound in the sperm pellet was identified as DHT when this steroid was used as the substrate; the remaining radioactivity consisted of 3 alpha-diol and delta 16-3 alpha-ol. Investigations of ejaculated sperm pellets gave similar results apart from the additional identification of 5 alpha-androst-16-en-3 one (delta 16-3-one) and 5 alpha-androst-16-en-3 beta-ol (delta 16-3 beta-ol (delta 16-3 beta-ol).
Steroids 1978 Mar
PMID:Uptake and metabolism of androgens by bovine spermatozoa. 66 70

The in vivo retention of 3-H-testosterone, dihydrotestosterone (DHT), 3alpha-androstanediol (3alpha-DIOL), 3beta-DIOL, androstenedione, progesterone and cortisol by renal cytoplasm and nuclei of male and female mice was studied. Testosterone was the major androgen isolated from cytoplasm and nuclei following testosterone or androstenedione administration. By contrast, DHT was the major intracellular androgen after DHT, 3alpha- or 3beta-DIOL injection. The uptake of 3-H-testosterone or 3-H-DHT was abolished by excess unlabeled testosterone, DHT or cyproterone acetate. Androgen concentrations in kidney fractions from female mice were similar to those from males. There was no appreciable concentration of the isolated steroids following 3-H-progesterone administration. 3H-cortisol was concentrated in both cytoplasm and nuclei but was not displaced by non-radioactive androgens. These findings suggest that in contrast to prostate, mouse kidney can concentrate both testosterone and DHT. However, since testosterone is the major androgen in blood and since it is not metabolized in kidney, it is the major effector androgen in this organ. Androstenedione is active via conversion to testosterone while DIOLS are androgenic via metabolism to DHT.
Steroids 1975 Jan
PMID:In vivo androgen retention in mouse kidney. 111 Nov 70

Isolated granulosa cells and theca from proestrous hamsters alone and in recombination, were cultured in order to study steroidogenic capacity of this tissue. Cells from medium size antral follicles (100-300 mum diam.) and large preovulatory follicles (500 plus mum diam.) were used. Steroids were measured by radioimmunoassay. Cultures of cells derived from both sizes of follicles made significant amounts of progesterone for up to 6 days in tissue culture. The preparations from the medium sized antral follicles synthesized little or no estrogen. Of the cells harvested from the preovulatory follicles, the granulosa and theca made moderate amounts of estradiol-17beta while the recombined system made similar to 5 times the estradiol-17beta made by theca or granulosa alone. The results indicate that in the in vitro system used: 1) The hamster follicle cells are similar to other species in that they spontaneously luteinize in culture and secrete large amounts of progesterone, 2) Androgen accumulation is greatest in media from cultured theca of preovulatory follicle, 3) A synergism between theca and granulosa of the large preovulatory follicle exists to effect maximal estrogen synthesis, and 4) Estrogen synthesis is short-lived in vitro in contrast to continued progesterone production.
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PMID:Progesterone, androstenedione, testosterone, estrone, and estradiol synthesis in hamster ovarian follicle cells. 111 80

A new technique that permits measurement of Androgen-Binding Protein (ABP) is validated by reproducibility, linearity and correlation studies. Using this apparatus allowing Scatchard plot analysis, it is also possible to measure association and dissociation rate constants. In addition, it is a very useful tool for a rapid screening of ABP binding capacity during a chromatographic stepwise purification.
Steroids 1988 Oct
PMID:Validation of a new system for androgen binding protein measurement. 325 40

Androgen can directly modulate the induction of steroidogenic enzymes by FSH (follicle stimulating hormone) in ovary granulosa cells. In studies of its mechanism of action, we examined the androgen effect on granulosa cell interaction with lipoproteins, the physiologic source of cholesterol. After granulosa cells were cultured for 48 hours with and without androgen and/or FSH, the cells were incubated for 24 hours with 125I-lipoproteins [human high density lipoprotein (HDL), rat HDL, or human low density lipoprotein (LDL)]. The media were then analyzed for lipoprotein protein coat degradation products (mainly 125I-monoiodotyrosine) and progestin [mainly 20 alpha-dihydroprogesterone (20 alpha-DHP)]. In the absence of FSH and androgen, 2 X 10(5) granulosa cells degraded basal levels of all three lipoproteins, but produced no measurable 20 alpha-DHP. The addition of 10(-7) M androstenedione (A), testosterone (T), or 5 alpha-dihydrotestosterone (DHT) had no effect on lipoprotein protein degradation or 20 alpha-DHP production. FSH alone stimulated lipoprotein protein degradation by 50 to 300% while the addition of androgen synergistically augmented the FSH-stimulated 20 alpha-DHP production as well as protein coat degradation of all three lipoproteins. DHT and T were both effective, indicating that androgens themselves, and not estrogen products, were responsible for the effect on lipoprotein protein degradation and 20 alpha-DHP production. The addition of a 10-fold excess cyproterone acetate (an anti-androgen) inhibited the effect of T, suggesting that the action of T was mediated by the granulosa cell androgen receptor. Androgen and FSH also synergistically stimulated the production of 3H-progestin when the granulosa cells were incubated with either 3H-cholesterol ester core labeled human HDL or similarly labeled human LDL. This report demonstrates that androgen, in combination with FSH, augments the steroidogenic pathway of the granulosa cell from the degradation of lipoprotein and utilization of the cholesterol ester core, to the production of progestin product.
Steroids 1984 Jan
PMID:Androgen and FSH synergistically stimulate lipoprotein degradation and utilization by ovary granulosa cells. 624 Aug 1

Androgen binding was studied in cytosol of human fibroblasts at 4 degrees C. When 5 alpha-dihydrotestosterone (DHT) was the ligand, a curvilinear Scatchard plot was seen, which was resolved into two components: I the androgen receptor (AR), Kd = 0.12-0.44 nM, and II a low affinity species, Kd = 6.3-28 nM. The same cytosol demonstrated only type I binding for 3H-methyltrienolone (MTr), Kd = 0.10-0.40 nM. The AR, i.e., 3H-MTr binding activity, eluted at 440,000 d by gel filtration chromatography in pre-labeling and post-labeling experiments. When the ligand was 3H-DHT, binding activity in the 10,000-45,000 d range was seen in addition to AR. Thus, saturable nonreceptor steroid binding was seen for DHT but not for MTr. The latter is the preferred ligand for the study of the AR in this system.
Steroids 1984 Feb
PMID:Cytosol androgen receptor (AR) in human skin fibroblasts: characterization of the binding reaction and differentiation from androgen binding molecules of lower affinity. 652 37

Effects of androgens on progesterone accumulation, utilization of exogenous progesterone and accumulation of [4-14C]progesterone metabolites by rat granulosa cells in culture were studied. Androgen increased progesterone accumulation in cultures without exogenous progesterone and slowed the overall decline of progesterone concentration in cultures supplemented with exogenous progesterone. Both aromatizable testosterone and nonaromatizable 5 alpha-dihydrotestosterone decreased [4-14C]progesterone utilization by granulosa cells by 12 to 30%. This effect was observed irrespective of whether the cells were continuously exposed to androgens or only pre-exposed. In he same experiments, androgens decreased conversion of radiolabeled progesterone to 20 alpha-hydroxy-4-pregnen-3-one by 11 to 50% and to 5 alpha-pregnane-3 alpha, 20 alpha-diol by 26 to 49%. Accumulation of 3 alpha-hydroxy-5 alpha-pregnan-20-one was not altered in 3 h incubations and was increased by up to 43% in 24 h incubations by androgen treatment. It is suggested that androgens alter progesterone catabolism by granulosa cells by decreasing 20 alpha-hydroxysteroid dehydrogenase activity and that this effect may contribute to overall stimulatory action of androgens on progesterone accumulation.
Steroids 1983 Sep
PMID:Androgenic modulation of progesterone metabolism by rat granulosa cells in culture. 667 94

Testosterone (17 beta -hydroxy-4-androsten-3-one ; T) and dihydrotestosterone (17 beta -hydroxy-5 alpha -androstan-3-one ; DHT) concentrations were determined by radioimmunoassay in different fetal tissues taken from male guinea-pigs. Androgen concentrations were maximal in the components of the Wolffian duct (vas deferens, epididymis, seminal vesicle) and the urogenital sinus (urogenital tubercle, prostate) when these tissues are differentiating between days 28 and 36 (T = 320 to 1450 and DHT = 200 to 860 pg/10 mg of tissue). During the same period circulating testosterone is taken up by the non-specific tissues (intestine, diaphragm) to a lesser degree (150 to 250 pg/10 mg) as well as by hypothalamus and hypophysis (100 to 170 pg/organ). After this uptake phase, T declines in the non-specific tissues to minimal concentrations (less than 10 pg/10 mg). Compared to the situations in the diaphragm and intestine, DHT concentrations were significantly higher in both urogenital sinus and Wolffian duct components, and T concentrations were significantly higher only in the Wolffian ducts components. In the bladder, T and DHT levels were significantly higher than those of the androgen-independent tissues.
Steroids 1981 Aug
PMID:Quantification of endogenous testosterone and dihydrotestosterone in fetal tissues from male guinea-pig. 730 30

Androgen-binding protein (ABP) in rat epididymal cytosol and sex hormone-binding globulin (SHBG) in rabbit serum and SHBG purified from human serum were active-site-directed photoaffinity radiolabeled with 17 alpha-[(E)-2-[125I]iodoethenyl]androstan-4,6-dien-17 beta-ol-3-one ([125I]1). The interaction of this compound with binding components in epididymal cytosol was dependent on exposure of the mixture to ultraviolet light and on the duration of exposure. Photolysis in the presence of [125I]1 and 5 alpha-dihydrotestosterone (5 alpha-DHT) resulted in a 40% inhibition of binding of [125I]1 to cytosolic components. These result indicate that, while [125I]1 interacted with 5 alpha-DHT binding sites, it also formed adducts with other sites. To characterize the labeled species, the photolysis mixture was subjected to electrophoresis under denaturing and reducing conditions. Autoradiography of the gel revealed that ABP and SHBG were labeled with [125I]1, but in cytosol and serum, higher and lower molecular weight components were also labeled. Purified SHBG was labeled, but no labeled contaminating protein was detected. The presence of 5 alpha-DHT completely inhibited [125I]1 photolabeling of human and rabbit SHBG and of ABP. However, in cytosol, the presence of 5 alpha-DHT also eliminated photolabeling to a component that may be albumin, but 5 alpha-DHT did not affect [125I]1 photolabeling of other contaminating proteins in cytosol. Thus, while [125I]1 is an effective photoaffinity radiolabel for ABP and SHBG, the observation that it also photolabels other proteins limits its practical use to the radiolabeling of purified ABP and SHBG preparations.
Steroids 1995 Mar
PMID:Active-site-directed photoaffinity radioiodination of androgen-binding proteins. 779 27


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