Effectiveness of several androgens in stimulating kidney hypertrophy, a secondary sexual character, in castrated male three-spined sticklebacks, Gasterosteus aculeatus

The effectiveness of different androgens in stimulating hypertrophy of the kidney tubules, a male secondary sexual character, was studied by injecting castrated male sticklebacks with androgens at doses of 0.008–25 μg∙g body weight −1 ∙day −1 (or control injections were given) for 3 weeks. The doses (μg/g) needed to give 50% stimulation of the kidney epithelium height were as follows: 11-ketotestosterone (OT), 0.047; 11β-hydroxyandrostenedione, 0.070; 11-ketoandrostenedione, 0.11; 5α-androstane-3,11,17-trione, 1.1; 5α-dihydrotestosterone, 1.8; 17β-hydroxy-5α-androstane-3,11-dione, 3.0; and testosterone, 15.2. Androstenedione and 5β-androstane-3,11,17-trione did not reach half-effectiveness at the dose tested (5 μg/g). It is suggested that OT is the physiologically relevant androgen in this case.