Vasopressin and glucoprivic-feeding behavior: a new perspective on an 'old' peptide

The feeding responses induced by systemic administration of 2-deoxy-D-glucose (2-DG) and paraventricular hypothalamic injection of norepinephrine were assessed in Brattleboro rats deficient in vasopressin (VP). Controlling for the non-specific complications of diabetes insipidus, it was found that Brattleboro rats have a deficient 2-DG-feeding response, but an essentially normal noradrenergic-feeding response. Specific carbohydrate appetite abnormalities were also demonstrated. It is argued that VP influences 2-DG feeding by mobilizing endogenous energy stores following its acute release from the hypothalamoneurohypophysial system. A new function is thus ascribed for VP and the neural lobe of the pituitary. It is suggested that VP plays a role in stress-induced feeding and in specific aspects of carbohydrate appetite. The potential relevancy of vasopressin perturbations to bulimia nervosa and to the Prader-Willi obesity syndrome is also discussed.