Studies on the hypophysectomized ferret. V. ─Effect of hypophysectomy on the response of the female ferret to additional Illumination during anœstrus

Abstract

Bissonnette (1932), following up his work on the European starling, recently reported that anœstrous ferrets could be brought into œstrus by exposure to additional illumination. The animals were given 6-6½ hours electric light each evening from October 12 onwards. Full œstrus occurred in 38-64 days, i. e. , well within the normal anœstrous period, and ovulation followed copulation. Males subjected to similar treatment showed endocrine activity of the testis, with resulting willingness to copulate, but spermatogenesis failed to progress beyond the secondary spermatocyte stage. In view of the general correlation between the gonads and the anterior pituitary body and of the activation of the anœstrous female ferret by injection of anterior lobe preparations (Hill and Parkes, 1930), it seemed probable that the effects reported by Bissonnette were due to stimulation of the anterior lobe by the light treatment. If this were so the response to light should be obliterated by hypophysectomy. Experiments carried out on these lines on female ferrets are reported below. In the course of the work, we have fully confirmed Bissonnette's observations on the induction of œsturs in the anœstrous ferret by additional illumination.