Long-Term Studies of Feeding Behavior of Obese, Diabetic, and Viable Yellow Mutant Mice under Ad Lib. and Operant Conditions

Abstract

The feeding behavior of obese ( ob/ob), diabetic ( db2s/ db2s), and viable yellow ( Avv/a) mice was assessed in 2 separate experiments. When given access to solid food and sweet liquid food simultaneously, fat mutant mice ingest large quantities of sweet liquid food and gain weight more rapidly than controls. The behavior of diabetic and obese mice in this situation is quite similar. When given access to sweet liquid food reinforcement in an operant conditioning situation the behavior of the three mutant genotypes differs. The response rate of obese mice does not appear to be schedule dependent, while that of viable yellow mice clearly is schedule dependent. The response rates of viable yellow mice are consistently higher than the rates of their controls. The behavior of a diabetic mouse does not appear different from that of a control mouse in this situation. The use of mutant genotypes as “natural preparations” comparable to experimentally induced lesions is discussed.