Satietin, a blood-borne glycoprotein in the regulation of food intake.

Satietin and satietin-D, two closely related 50,000 dalton anorectic glycoproteins were isolated from human serum. The isoelectric point of satietin is 7.0, it contains 14-15% amino acids and 70-75% carbohydrates. Satietin-D has an isoelectric point of 3.0, a protein content of 20-22% and a carbohydrate content of 55-60%. Both satietin and satietin-D are potent, long-acting and highly selective suppressants of food intake in the rat. The hypothesis was forwarded that satietin and satietin-D may belong to a system which brings into being the rate-limiting blood-borne satiety signalization in the negative feedback of food intake.