Metabolism of C14-labeled acetone, acetate and palmitate in fasted pregnant and nonpregnant guinea pigs

Abstract

Metabolism of acetone-2-C14, Na acetate-2-C14, and Na palmitate-1-C14 was compared in normal and pregnant ketotic guinea pigs. Expired CO2, lipids, urine, liver tissue and acetone bodies were quantitated and assayed for radioactivity. After acetone-C14 injections, pregnant ketotic, as well as nonpregnant guinea pigs injected with carrier acetone, metabolized markedly less C14 as the blood concentration of acetone was progressively elevated. The data showed that the actual milligrams of free acetone utilized remained fairly constant regardless of the size of the body acetone pool. After acetate-C14 injections, pregnant fasted guinea pigs utilized less C14 for CO2 excretion and more C14 for biosynthesis than the nonpregnant fasted group. The difference in CO2 specific activity with regard to size of the body acetate pool is discussed. After palmitate-C14 injections, the mean specific activity of the CO2 was greater in the pregnant fasted than in the nonpregnant fasted animals. Since the liver fat content of the former was lower, the data indicate a faster turnover rate of a smaller fatty acid pool.