The effect of starvation on obese mice.

Plasma level of total and acylcarnitine and the activities of carnitine acetyltransferase (CAT) and carnitine palmitoyltransferase (PCT) in liver and CAT in brown fat were determined in young obese (ob/ob) mice and their littermates during starvation. Plasma levels of acylcarnitine and beta-hydroxybutyrate rose equally in both groups. Total carnitine levels, however, decreased in lean and rose in obese animals. Hepatic PCT and phosphoenolpyruvate carboxykinase activities rose more in lean than obese mice and brown fat CAT activity decreased in the obese group. Fatty acid synthetase activity decreased equally in the liver in obese mice and their lean littermates.