Gonadal regression induced by caloric restriction is not mediated by the pineal gland in deer mice (Peromyscus...

The role of the pineal gland in mediating reproductive regression in response to nonphotoperiodic cues was assessed. A proportion of deer mice (Peromyscus maniculatus) undergo gonadal regression subsequent to moderate food restriction. The reproductive regression after inanition qualitatively and quantitatively resembles short-day-induced regression. The physiological mechanisms responsible for gonadal regression after food restriction are unknown. The hypothesis that the mechanisms underlying photoperiodic responsiveness also mediate testicular regression caused by reduced food consumption was tested. Males were pinealectomized or received sham operations. Upon recovery, food availability was restricted to 70% of ad libitum intake. After 8 weeks, the reproductive condition was examined. Pinealectomy did not prevent gonadal regression, suggesting that the pineal gland does not mediate caloric information in this species.