The effect of intracerebroventricular insulin on the hypothalamic and neurohypophysial oxytocin activity in euhydrated or dehydrated rats.

Rats dehydrated up to four days were given intracerebroventricularly insulin in a daily dose of 100 ng. Insulin decreased significantly the hypothalamic and neurohypophysial oxytocin content in euhydrated rats. In dehydrated animals the oxytocin activity in the hypothalamo-neurohypophysial system, markedly depleted after deprivation of water, could be further reduced by intracerebroventricular treatment with insulin. These results seem to suggest a possible regulatory role of brain insulin in the mechanisms of oxytocin release.