Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P56851 (epididymal)
 11,273 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

To determine if ram principal cells can synthesize or metabolize testosterone, or metabolize other steroids present in rete testis fluid, principal cells from the initial segment, central caput, and proximal corpus epididymidis were isolated and cultured in a floating collagen matrix with medium containing 20% dialyzed rete testis fluid. In the first experiment, each matrix was washed twice in testosterone-free medium on day 2.8, transferred into culture medium containing 100 nM of a tritiated steroid and incubated for 4 hours at 34 C. The tritiated steroids were pregnenolone, 5-androstene-3 beta,17 beta-diol, progesterone, 4-androstene-3,17-dione, testosterone, and dihydrotestosterone. Since testosterone was not formed from 5-androstene-3 beta,17 beta-diol or 4-androstene-3,17-dione, testosterone synthesis by ram principal cells is unlikely Pregnenolone and 5-androstene-3 beta,17 beta-diol were not metabolized and only slight metabolism of dihydrotestosterone occurred. Progesterone, 4-androstene-3,17-dione, and testosterone were metabolized to 5 alpha-reduced products tentatively identified as 5 alpha-pregnane-3,20-dione and 5 alpha-pregnan-3 beta-ol-20-one and/or 5 alpha-pregnan-20 alpha-ol-3-one; 5 alpha-androstane-3,17-dione and 5 alpha-androstan-3 alpha-ol-17-one, and dihydrotestosterone, respectively. The second experiment evaluated testosterone metabolism by both cultured principal cells and minced epididymal tissue. On day 1 of culture, during 12 hours the accumulation of dihydrotestosterone in medium from cells of the central caput was 48 X and 1.1 X that in medium from cells of the initial segment and proximal corpus epididymidis.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Steroidogenesis and testosterone metabolism in cultured principal cells from the ram epididymis. 362 61

We examined the production in vitro of 5 alpha-reduced metabolites from testosterone by the rat epididymis during pubertal maturation. Minced caput and cauda epididymides from 30-,45-, and 55-day-old rats were incubated with [3H] testosterone for 2h. Analysis of the radioactive metabolites revealed both similarities and differences in the metabolic patterns compared to those reported for adult rats. As in adults, 5 alpha-dihydrotestosterone was the most abundant metabolite produced by both epididymal segments at all three ages, and it was formed in larger quantities in the caput epididymidis than in the cauda. However, [3H] testosterone metabolism by the epididymis of the immature rat was characterized by a lower formation of 5 alpha-androstane-3 alpha,17 beta-diol and higher production of 5 alpha-androstane-3,17-dione than in adults. Production of these two metabolites by the caput region increased and decreased respectively, toward adult levels, with increasing age. In addition, the amount of [3H] testosterone metabolized was higher with tissues from prepubertal rats (30 days of age) than with those from rats 55 days of age. These data suggest that testosterone metabolism in the caput begins to change to that of the adult during the period of pubertal maturation but apparently not until later in the cauda epididymidis.
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PMID:Age-related changes in the metabolism of [3H] testosterone in vitro by the epididymis of the immature rat. 729 17

The in-vitro metabolism of [3H] testosterone by the epididymis of the pubertal rat (55 days of age) has been examined after short-term bilateral and unilateral castration and androgen replacement. Bilateral castration did not decrease the metabolism of [3H] testosterone, but did result in a decline in the proportion of 5 alpha-dihydrotestosterone produced and an increase in that of 5 alpha-androstane-3 alpha, 17 beta-diol, androsterone and 5 alpha-androstane-3,17-dione. Changes in metabolism occurred in the caput within 2 days after surgery, but not until 5 days after surgery in the cauda epididymidis. Daily testosterone treatment, which maintained prostatic growth in bilaterally castrated animals, did not restore normal androgen metabolism and increased further the production of androsterone and 5 alpha-androstanedione by the cauda. In unilaterally castrated animals, androgen metabolism in epididymal tissue from the operated side was normal in the cauda but was indistinguishable in the caput from that of bilaterally castrated rats. These results indicate that (a) androgen metabolism by the caput, compared to that by the cauda, responds more quickly to androgen withdrawal and (b) that in the short term, normal androgen metabolism by the caput, but not the cauda, is dependent upon the presence of the ipsilateral testis. Furthermore, testosterone alone proved an inadequate replacement for bilateral castration which implies that the pubertal rat testis secretes additional compounds which are essential for normal function of the epididymis.
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PMID:Effects of short-term bilateral and unilateral castration and androgen replacement on the metabolism of [3H] testosterone in vitro by the epididymis of the immature rat. 729 18