Cloacal gland of the Japanese quail: androgen dependence and metabolism of testosterone.

A cloacal gland complex whose growth and development is androgen-dependent exists in the Japanese quail. In-vitro incubation studies of the cloacal gland using 4-14C-labelled testosterone as substrate allowed the positive identification of five metabolites: androstenedione, 5 beta-dihydrotestosterone (5 beta-DHT), 5 beta-androstane-3 alpha, 17 beta-diol, 5 alpha-DHT and 5 alpha -androstane-3 alpha, 17 beta-diol. More polar metabolites, not yet chemically identified, were detected in trace amounts. Androstenedione appeared to be the main testosterone metabolite in immature birds while in mature birds on long daylengths testosterone was preferentially metabolized to 5 alpha-DHT. This change may have been in response to the higher levels of plasma steroids found in mature birds. When various testosterone metabolites, contained in silicone elastomer capsules, were implanted s.c. into castrated birds maintained on a photostimulatory light regime, 5 alpha-DHT, 5 alpha-androstane-3,17-dione, androstenedione and 5 alpha-androstan-3 alpha-ol-17-one were shown to be equipotent with testosterone in stimulating the development of the cloacal gland. 5 alpha-Androstane-3 alpha, 17 beta-diol and 5 alpha-androstan-3 beta-ol-17-one stimulated some growth while 5 beta-DHT, 5 alpha-androstane-3 beta, 17 beta-diol, 5 alpha-androstane-3 alpha, 17 beta-diol, 5 beta-androstane-3,17-dione, androst-5-en-3 beta-ol-17-one and androst-5-ene-3 beta, 17 beta-diol were completely ineffective.