Topic
Pregnenolone
About: Pregnenolone is a research topic. Over the lifetime, 3539 publications have been published within this topic receiving 126444 citations. The topic is also known as: (3b)-3-hydroxy-Pregn-5-en-20-one & 3-Hydroxypregn-5-en-20-one.
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TL;DR: The methodology validated here, allows femtomoles of neurosteroids, including the sulfates, found in small brain samples (at least equal to 10 mg) to be quantified simultaneously, and high sensitivity and accuracy were obtained.
150 citations
TL;DR: The hypothesis that ACTH controls steroidogenesis by determining the rate of efflux of mitochondrial pregnanolone and hence the extent of the feedback inhibition by pregnenolone of its own synthesis is found to be consistent with the data obtained.
148 citations
TL;DR: Findings suggest that neurosteroids and sex steroids may affect brainrepair by down‐regulating gliotic tissue in adult male rats after a penetrating wound of the cerebral cortex and the hippocampal formation.
148 citations
TL;DR: The fetal testis has highest Leydig cell and endogenous steroid concentrations and the new Leydigs cell generation after 15 days has a persistently low steroid concentration through puberty.
Abstract: Endogenous androgens (androstenedione, testosterone, 5a-dihydrotestosterone and 5a-androstane-3a,1713-diol), and some of their C21 precursors (pregnenolone, progesterone and 17-hydroxyprogesterone) were measured in rat testes between Day 18.5 of pregnancy and Day 64 postpartum, and correlated with numerical densities of Leydig cells. The latter parameter showed an early maximum on Day 19.5 of the fetal period, a nadir on Day 15 postpartum, and a gradual increase thereafter. The two dominating androgens, testosterone and 5a-androstane-3a,17(3-diol, had similar levels until 15 days of age, but the 5a-diol predominated thereafter. The total steroid content per Leydig cell was highest on Day 18.5 of gestation (77 ng/10’ cells). A decline started already in utero, and reached a nadir of 5 ng/10’ cells on Day 29. Thereafter, a slight increase occurred with advancing age. It is concluded that: 1) The fetal testis has highest Leydig cell and endogenous steroid concentrations. A nadir in these parameters is seen 2-4 wk postpartum. The Leydig cell concentration increases around puberty on Days 40-60, but only a slight concomitant increase occurs in steroids. 2) A sharp decline in steroid content per Leydig cell occurs during the last fetal days, but the postnatal decline of testicular steroids is due to Leydig cell loss. 3) The new Leydig cell generation after 15 days has a persistently low steroid concentration through puberty. 4) The relative proportions of endogenous steroids are similar in the fetal and immature testes, but the pubertal increase in steroidogenesis is characterized by increased ratios of C19/C21 steroids, 5a-reduced/3-keto-4-ene androgens, and 1 7�3-hydroxy/1 7-keto androgens.
148 citations
TL;DR: CYP3A and Pgp responses to CYP3A inducers are regulated independently in rat liver and, at the dosage regimen used, this study shows that Pgp expression and regulation are gender specific.
147 citations