Glucose solution intake in the rat: the specificity of postingestive satiety

Hungry rats were permitted to drink a concentrated glucose solution to 'satiety', as indicated by (1) cessation of drinking, (2) the appearance of behaviors correlated with satiety (grooming and exploring followed by resting), and (3) refusal to drink appreciable further quantities when access to the solution was prolonged. Yet such rats returned to vigorous and prolonged feeding when offered laboratory pellets, powered chow, or even glucose itself in powered form. "Satiety" for a glucose solution does not reflect a generalized suppression of hunger or of a specific carbohydrate hunger. Its properties are more specific than existing theories of energy intake regulation would lead us to suppose.