Role of the pineal gland in the activity of nervous structures involved in sexual processes of the male rat.

1. The role of the pineal gland and melatonin in the regulation of the sexual processes of the male rat has been studied by means of the O2-uptake of brain areas that are involved in these processes, i.e. the hypothalamus, amygdala, septal area and posterior cortex. 2. Inhibition of the O2-uptake of the above mentioned nervous structures was observed in the blinded and/or melatonin-treated rats or castrated + blinded rats. 3. The testes also showed a decreased O2-uptake when the rats were blinded and/or melatonin-treated.