Influence of the Pineal Gland on Gonadal Maturation in the Japanese Quail¹

Abstract

Pinealectomy resulted in decreased ovarian weight, decreased oviducal and adenohypophyseal weights and delayed onset of oviposition in birds exposed to a stimulatory 16-hr photoperiod (16L:8D). This delay in maturation occurred only in females and was transient. The effects of pinealectomy were reversed by multiple pineal implants. Pinealectomized females exposed to continuous light (24LL) showed a similar delay in maturation. Hence, the pineal gland in female Coturnix has a stimulatory influence on the time of ovarian maturation. When ovarian growth rate was markedly reduced by treatment with a nonstimulatory photoperiod (8L:16D), pinealectomy was without effect. Exogenous doses of melatonin did not alter gonadal growth in intact females or males, both juvenile and adult. (Endocrinology83: 1237, 1968)