SOME EFFECTS OF ANDROGENS ON THE ADULT MALE FUNDULUS

¹ From Trinity College and the Mt. Desert Island Biological Laboratory

Adult male Fundulus hypophysectomized during the breeding season were injected intraperitoneally with 8 mg. of testosterone propionate during a 42 day period. The hormone maintained the yellow body coloration characteristic of a breeding male. The hormone did not maintain the testis in the breeding condition. The testicular ducts were maintained better than they were in the controls. There was slightly more spermatogenetic activity than in the controls. Like amounts of testosterone injected intraperitoneally into normal fish over a similar period had no effect on the testis and only partially maintained the yellow coloration of the body.

Normal adult male fish injected intraperitoneally or intramuscularly with testosterone propionate (see text for dosage) during testicular involution and during the early stages of spermatogonial multiplications showed a marked activation of the testicular ducts and a slight stimulation of spermatogenesis. The yellow coloration of the body developed brilliantly in the treated fish. The above experiment was performed once for an 18 day period, and once for a 25 day period.

It is concluded that the yellow coloration of the body, characteristic of the breeding male, is stimulated by the male hormone, and the elaboration of the testicular duct system is influenced by this hormone. While a slight stimulation of spermatogenesis was observed, the degree of stimulation does not warrant the conclusion that in the intact animal the male hormone has any important spermatokinetic role.