Regulation of Epididymal Glutathione S-Transferases: Effects of Orchidectomy and Androgen Replacement

Publisher Website
Google Scholar
Abstract
Glutathione S-transferases, a family of enzymes that catalyze the conjugation of glutathione to a variety of substrates, are present in rat epididymis. To study the hormonal regulation of these enzymes in this tissue, adult rats were orchiectomized and implanted with empty or androgen-filled polydimethylsiloxane capsules. Orchiectomy alone significantly decreased caput-corpus epididymal glutathione S-transferase activity toward 2 substrates, 1-chloro-2,4-dinitrobenzene and trans-4-phenylbut-3-en-2-one, but had no effect on transferase activity toward the 3rd substrate, 1,2-dichloro-4-nitrobenzene. In contrast to these results, orchidectomy did not alter glutathione S-transferase activity toward these substrates in the cauda epididymidis. Androgen replacement with testosterone prevented the orchiectomy-induced decrease in caput-corpus glutathione S-transferase activity toward 1-chloro-2,4-dinitrobenzene and trans-4-phenylbut-3-en-2-one and had no effect on transferase activity toward 1,2-dichloro-4-nitrobenzene. The effects of 5.alpha.-reduced metabolities of testosterone were also studied. Both dihydrotestosterone and 5.alpha.-androstan-3.alpha., 17.beta.-diol maintained caput-corpus glutathione S-transferase activity toward 1-chloro-2,4-dinitrobenzene, although a lower dose of dihydrotestosterone was sufficient; these 2 androgens were unable to maintain activity toward trans-4-phenylbut-3-en-2-one and caused a suprastimulation of activity toward 1,2-dichloro-4-nitrobenzene above control values. The 3rd 5.alpha.-reduced androgen studied, 5.alpha.-androstan-3.beta.,17.beta.-diol had no effect on the transferase activity toward any of the 3 substrates. The epididymal glutathione S-transferases apparently are under separate control and are differentially regulated by testosterone and its 5.alpha.-reduced metabolites.
Keywords