OVARIAN STIMULATION IN THE IMMATURE FOWL BY DESICCATED AVIAN PITUITARIES1

Abstract

Immature female brown Leghorn chickens were injected daily with a saline suspension of ground, acetone-dried anterior lobes of chickens. Significant follicular stimulation, but no precocious ovulation, was observed in those treated from 1 to 90 days of age, from 30 to 65 days, and from 60 to 150 days, but not in those treated from 1 to 35 days. All stimulated ovaries were essentially normal in appearance, showing none of the hyperplastic, cystic growth observed after treatment with pregnant mare serum (PMS) or mammalian follicle stimulating hormone. Accelerated comb growth, indicating increased androgen secretion, was maintained in each group throughout the injection period. Such sustained comb stimulation cannot be produced by PMS, for cessation of growth and actual regression occur with prolonged treatment. These results (follicular stimulation, general normality of the treated ovaries, sustained comb growth) support the hypothesis that there are qualitative differences between avian and mammalian gonadotrophins.