Food and water intake of rats after intraperitoneal and subcutaneous administration of glucose, glycerol and sodium lactate

Glucose, glycerol and DL — sodium lactate were injected in various doses by intraperitoneal (IP) and subcutaneous (SC) routes in rats accustomed previously to a 24 hr-feeding, 24 hr-fasting schedule. Administration of isosmolar sodium chloride and measurement of water ingestion served as controls for osmotic effects. The three substances determined a dose-dependent feeding depression in the first half hour when administered IP. SC injections produced a much weaker and non dose-dependent feeding depression. Some doses prolonged the hypophagia up to three or even 24 hr. No relation can be established between the hypophagia and the concurrent hyperdipsia since the last effect does not depend on the route of administration. It is suggested that the hypophagia which followed IP administration was due to information of hepatic origin.