SOME EFFECTS OF SEX STEROIDS ON THE GONADS OF THE STARLING12

Abstract

Estradiol dipropionate and testosterone propionate, with the dosage and duration of treatment used, had no effect on the sexually inactive ovary. Estradiol and its dipropionate modified testes which were either inactive or sperm-producing. The effects found were 1) a suppression of spermatogenesis with a disappearance of all stages except the primary spermatogonial. Cells of this later stage became less numerous. 2) There was a marked hypertrophy of the intertubular tissue in which eosinophilic (Leydig) cells appeared. Cells for this hypertrophy appeared to come from the fibrous walls of the tubules. 3) There was a thickening of the walls of the testicular arterioles. Testosterone propionate neutralized the adverse effects of estradiol. The effects of estradiol seem to be due to a direct action on the testes. Testosterone treated starlings which were initially in the spermatocyte stage and were maintained on "short days" developed further into spermatogenesis than did controls. This result together with previous results lends support to the theory of Pfeiffer that in the bird, c? hormone supports the maturation of c? sex cells but not their sperma-togonial multiplication.