Testicular function in frogs implanted for 30 days. Measurements of testicular function in frogs implanted for 30 days with either Ch, DHT, or E2. A) Average GSI, (B) average diameter of seminiferous tubules, (C) number of I SPG, and number of cysts containing (D) II SPG, (E) I SPC, and (F) II SPC were measured from 5–6 animals per treatment group. Each bar represents mean ± SEM. Dissimilar letters indicate significant difference between groups.