Lack of effect of bromocriptine and domperidone on arginine-vasopressin response to insulin-induced hypoglycemia in normal men.

In order to establish whether the arginine-vasopressin (AVP) increase evoked by insulin-induced hypoglycemia is mediated by a dopaminergic pathway, 16 normal men were given an insulin tolerance test (ITT) under basal conditions and after treatment with the dopamine agonist bromocriptine (2.5 mg by mouth) (eight subjects) or the dopamine antagonist domperidone (10 mg i.v.) (eight subjects). In addition, five out of eight subjects in each group were treated with higher doses of bromocriptine (5 mg by mouth) or domperidone (20 mg i.v.). Basal and ITT-stimulated AVP secretion was not modified by the drug treatments, suggesting that dopamine is not involved in the regulation of AVP secretion in response to insulin-induced hypoglycemia.