Influence of castration and testosterone on pineal multi-unit activity in quail

Pineal multiple unit electrical activity was recorded in unanaesthetized quail maintained under a short or long daily photoperiod. Both spontaneous and flash-induced multiple unit firing were recorded in intact, castrated or superior cervical ganglionectomized birds. The effects of testosterone administration were tested in each experimental group. 10 Whereas orchidectomy led to a substantial rise in pineal multi-unit activity (MUA), testosterone propionate injection resulted in a markedly decreased MUA in castrates. A smaller decrease in MUA was caused by androgen treatment in intact or ganglionectomized birds. Androgen treatment of controls and ganglionectomized quail was not so effective in reducing pineal activity as was lengthening the photoperiod from 6L-18D to 18L-6D. 20 Repetitive photic stimulations resulted in a significant suppression of pineal MUA in all intact, castrated and ganglionectomized quail, whether or not testosterone was administered.