Photoperiodic control of testis activity in the vole, Microtus agrestis

Abstract

In voles, growth of testes and the onset and maintenance of their spermatogenic and endocrine activity are influenced by light. From experiments employing several different photoperiods recurring every 12, 24, 36 or 48 hr, it seems that the effect of a photoperiod depends on the time of its occurrence during the day. Voles appear to have an endogenous circadian rhythm of photosensitivity. It is suggested that testes mature more rapidly or are maintained in a more active state if the external light stimulus coincides with the postulated endogenous photosensitive period. (28 references)