Doses of 100 or 200 µg/day of one of the salmon preparations (G-100) maintained the normally enlarged testes, spermatogenic activity and enlarged accessory sexual structures (epididymis and kidney sex segment) in groups of 5 surgically hypophysectomized lizards in the spring. Lower doses of salmon gonadotropin (1 or 10 µg/day) failed to maintain testis function.

Injection of l00-µg salmon G-100 pituitary extract into groups of seven to eight lizards every other day for 15 or 29 days promoted testicular growth and normal spermatogenesis in Anolis with naturally regressed gonads in the fall. Lower doses (50 and 10 µg) of this pituitary extract had only slight effects on testicular recrudescence. A second more highly purified salmon pituitary extract (DEAE), judged to be 5 times more potent than the G-l00 on the basis of bioassays in goldfish, was found to be about 2-3 times more potent than the G-100 preparation with regard to testicular recrudescence when tested in groups of eight lizards. Also, some stimulation of interstitial cell activity was obtained with the more purified preparation.

Responses of the lizard to the salmon extracts are compared with the responses to ovine FSH and LH in simultaneous studies. Characterization of the salmon gonadotropin in terms of these two types of gonadotropic activities is not possible since the male lizard shows similar qualitative responses to both FSH and LH. Quantitatively, the relative potencies of the available salmon extracts resemble that of the ovine NIH-LH standard.