The hypothalamic and neurohypophysial vasopressor and oxytocic activities as influenced by beta-adrenergic blockade during long-term dehydration in the white male rat.

Rats dehydrated up to 12 days were given intraperitoneally propranolol hydrochloride in daily dose of 1.0 mg/100 g of initial body weight. In not dehydrated animals the only dose of propranolol increased significantly the vasopressin and oxytocin release from the neurohypophysis. In dehydrated animals propranolol restrained somewhat the decrease of vasopressin in the neurohypophysis, but intensified the vasopressin depletion in the hypothalamus. The oxytocic potency of both the neurohypophysis and hypothalamus decreased progressively in animals deprived of water. Propranolol potentiated this effect of osmoreceptor stimulation.