Influence of (-)-hydroxycitrate on lipigenesis in chickens and rats

The influence of (-)-hydroxycitrate on in vitro rates of fatty acid synthesis in chicken and rat liver and in rat adipose tissue was investigated. Following acute and chronic administration of (-)-hydroxycitrate to chickens and rats, changes in rates of fatty acid synthesis in vivo and in lipogenic enzyme activities were also determined. Addition of 1 mM (-)-hydroxycitrate to a buffer containing 10 mM glucose and liver slices from chickens or rats depressed the rate of 3H2O incorporation into fatty acids. Acute administration of (-)-hydroxycitrate to chickens and rats also depressed in vivo rates of fatty acid synthesis in the livers of these species. Chickens appeared to be more sensitive to the inhibitory effects of (-)-hydroxycitrate than did rats. (-)-Hydroxycitrate was incorporated into the diets fed to the chickens and rats. Hepatic citrate cleavage enzyme activities were increased several fold in livers of chickens and rats fed (-)-hydroxycitrate. However, the rates of fatty acid synthesis in chicken and rat livers were depressed when expressed per g liver. Livers of chickens fed (-)-hydroxycitrate for 14 days were enlarged. Dietary (-)-hydroxycitrate did not depress rates of fatty acid synthesis per liver in these birds. Consumption of (-)-hydroxycitrate did not alter liver weight in rats. In vivo rates of fatty acid synthesis in rat adipose tissue were not influenced by consumption of a diet containing 52.6 nmoles (-)-hydroxycitrate/kg diet. Plasma triglyceride levels were increased two-fold in chickens, but unchanged in rats, fed (-)-hydroxycitrate for 2 to 3 weeks. There are species-specific as well as organ-specific responses to (-)-hydroxycitrate.