Modification of mammalian sexual cycles. V. The avenue of reception of sexually stimulating light.

Abstract

Female ferrets were subjected to added lighting a) without hoods, b) with hoods exposing the eyes through holes, c) with heads covered by light tight hoods, for considerable periods each night. Completely covering the eyes delayed oestrus. Those whose hoods allowed light to enter the eye were not delayed. Exposure of the body to light seemed to have no effect. Even in animals which slept a lot during the added light periods oestrus was observed to come early, showing that the mere closure of the eye did not prevent the light from affecting the sexual mechanisms. All evidence seems to indicate that the eyes are the receptors for photoperiodic sexual stimulation in ferrets.