Major Testosterone Metabolites Research Articles

Metabolism of testosterone by preparations from the rat testis

Seminiferous tubules isolated from immature and adult rats were incubated with [ 14C] testosterone. Androstanediol and androstenedione were the major metabolites; dihydrotestosterone and androsterone were produced in lesser amounts. Cell suspensions of spermatocytes prepared from tubules of immature rats formed dihydrotestosterone as the major metabolite of testosterone. Smaller amounts of androstanediol were formed and no androsterone was detectable. The results show that spermatocytes in common with androgen responsive tissues have the capacity to metabolize testosterone to 5α-reduced products.

A prostatic cytosol receptor

Testosterone promotes the development of the prostate. It is partially transformed in the target organ into metabolites which have different effects upon the cells, and the activity of testosterone is possibly related to the formation of these derivatives (1, 2). In the uterus “cytosol”, there is a “receptor” for estradiol, the active estrogen. It has a sedimentation coefficient of approx. 8 S in dilute Tris buffer which can be converted in the presence of KCl≥0.3 M to a “KCl-5 S” form (3, 4). In the absence of the salt, this form is reversible to 8 S. This note reports the properties of a prostatic cytosol receptor of high affinity for androstanolone, a major metabolite of testosterone in the prostate, which displays interconvertibility of the heavy “8–9 S” and light “KCl-5 S” conformations, and binds potent “anti-androgens” .