DECREASED FOOD-INTAKE DOES NOT COMPLETELY ACCOUNT FOR ADIPOSITY REDUCTION AFTER OB PROTEIN INFUSION

The effects of recombinantly produced ob protein were compared to thos e of food restriction in normal lean and genetically obese mice. Ob pr otein infusion into ob/ob mice resulted in large decreases in body and fat-depot weight and food intake that persisted throughout the study. Smaller decreases in body and fat-depot weights were observed in vehi cle-treated ob/ob mice that were fed the same amount of food as that c onsumed by ob protein-treated ob/ob mice (pair feeding). In lean mice, ob protein infusion significantly decreased body and fat-depot weight s, while decreasing food intake to a much lesser extent than in ob/ob mice. Pair feeding of lean vehicle-treated mice to the intake of ob pr otein-treated mice did not reduce body fat-depot weights. The potent w eight-, adipose-, and appetite-reducing effects exerted by the ob prot ein in ob protein-deficient mice (ob/ob) confirm hypotheses generated from early parabiotic studies that suggested the existence of a circul ating satiety factor of adipose origin. Pair-feeding studies provide c ompelling evidence that the ob protein exerts adipose-reducing effects in excess of those induced by reductions in food intake.