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M Strömstedt, M Warner, C D Banner, P C MacDonald, J A Gustafsson
The role of brain cytochrome P450 (P450) in regulating the levels of the potent anesthetic steroid 3 alpha-hydroxy-5 alpha-pregnan-20-one (3 alpha-OH-DHP) has been investigated. By analogy with the elimination of androgen from its target tissues, we present evidence that it is 3 beta-hydroxy-5 alpha-pregnan-20-one (3 beta-OH-DHP) and not 3 alpha-OH-DHP that represents the major pathway for the formation of more polar metabolites and thus the elimination of the 5 alpha-reduced metabolites of progesterone from target tissues...
November 1993: Molecular Pharmacology
M L Thieulant, S Samperez, P Jouan
The binding of [3H]5 alpha-androstane-3 beta, 17 beta-diol (3 beta-Adiol) in the pituitary cytosol of prepubertal male rats was studied. The following criteria indicated that 3 beta-Adiol was bound to specific proteins and, in all probability, to the estrogen receptor. 1) The binding was of relatively high affinity and low capacity. 2) The complex was destroyed by proteolytic enzymes and by heating. 3) It was precipitable with protamine sulfate and 35% ammonium sulfate. 4) In sucrose linear gradients (5-20%), 3 beta-Adiol was bound in the 7S region...
April 1981: Endocrinology
M L Thieulant, T Benie, P Jouan
The concentrations of estradiol (E2) and 5 alpha-androstane-3 beta, 17 beta-diol (3 beta-Adiol) receptor were quantified in the pituitaries of male rats, aged 15--100 days. The available binding sites were measured directly in pituitary cytosol. E2 receptor levels reached a peak between days 22 and 30 and then declined slightly. 3 beta-Adiol-binding sites increased between days 15 and 37, reached a maximum level at the time of puberty (37--42 days of age), and then declined markedly to become undetectable on day 75...
April 1982: Endocrinology
C D Hastings, I Brekke, K Purvis, A Attramadal, V Hansson
The present paper demonstrates the presence of at least two 3-hydroxysteroid oxidoreductases (3-HSO) in rat testis, prostate, and epididymis cytosol preparations. The enzymes were either NADH or NDAPH dependent. Further investigation by Sephadex G-200 chromatogrphy revealed the presence of enzyme activities in the void volume (peak 1) and also eluting close to the methyl-carbonic anhydrase standard (mol wt, 34,000; peak 2). Enzyme activity in peak 1 was predominantly stimulated by NADH and that in peak 2 was stimulated mainly by NADPH...
December 1980: Endocrinology
T Saartok, E Dahlberg, J A Gustafsson
It is unclear whether anabolic steroids act on skeletal muscle via the androgen receptor (AR) in this tissue, or whether there is a separate anabolic receptor. When several anabolic steroids were tested as competitors for the binding of [3H]methyltrienolone (MT; 17 beta-hydroxy-17 alpha-methyl-4,9,11-estratrien-3-one) to the AR in rat and rabbit skeletal muscle and rat prostate, respectively, MT itself was the most efficient competitor. 1 alpha-Methyl-5 alpha-dihydrotestosterone (1 alpha-methyl-DHT; mesterolone) bound most avidly to sex hormone-binding globulin (SHBG) [relative binding affinity (RBA) about 4 times that of DHT]...
June 1984: Endocrinology
P Södersten, P Eneroth, T Hansson
Castrated male rats were treated with constant-release implants filled with testosterone, oestradiol-17 beta, 17 beta-hydroxy-5 alpha-androstan-3-one (5 alpha-dihydrotestosterone; DHT), 5 alpha-androstane-3 alpha, 17 beta-diol (3 alpha-Adiol) or 5 alpha-androstane-3 beta,17 beta-diol (3 beta-Adiol). Only testosterone activated the sexual behaviour of the rats. If combined with oestradiol, DHT or 3 alpha-Adiol induced the behaviour, but 3 beta-Adiol failed to have this effect. Oestradiol inhibited the in-vitro formation of [14C]Adiols from [14C]DHT by combined preoptic and hypothalamic tissue, but only when given in high doses...
December 1988: Journal of Endocrinology
P H Jellinck, R A Galbraith
Cobalt protoporphyrin (CoPP) administered subcutaneously to adult male rats caused a marked reduction in the conversion of 5 alpha-androstane-3 beta-17 beta-diol (3 beta-adiol) to its main triol derivative (6 alpha-atriol) by homogenates of the pituitary but not of the prostate or brain (ventromedial hypothalamus and cortex). No effect in the brain was observed when this heme analogue was infused intracerebroventricularly. 3 beta-adiol hydroxylase, the enzyme responsible for the reaction and whose main function is thought to be the elimination of dihydrotestosterone and its metabolites from target tissues, was also inhibited by CoPP and SKF-525A added in vitro...
December 1991: Journal of Steroid Biochemistry and Molecular Biology
L W Kao, J Weisz
A continuous flow incubation (perifusion) system was used to examine the effect of testosterone (T) and three of its 5alpha-reduced metabolites, dihydrotestosterone (DHT), 5alpha-androstane-3alpha, 17beta-diol (3alpha-Adiol) and its 3beta-epimer (3beta-Adiol) on LH and FSH release, induced by hypothalamic extract (HE). In the absence of steroids, successive identical pulses of HE, of 10 min duration each, administered at hourly intervals over a 8-hr period, caused highly reproducible release of LH and FSH. In experimental perifusions, the amounts of LH and FSH released in response to standard 10-min pulses of HE administered at hourly intervals during the continuous infusion of steroid for 4-6 hr were compared with the responses of the same pituitaries to the standard test pulses of HE given before the start of the steroid infusion and after its cessation...
February 1975: Endocrinology
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