Acetone Metabolism Research Articles

Acetone metabolism in sheep.

1. Entry rates of acetone were estimated in normal and ketonaemic sheep by using a constant-infusion technique with [(14)C]acetone. Entry rates were less than 1mg./min. in normal and 2-6mg./min. in ketonaemic sheep. 2. Only 1-2% of plasma glucose is derived from acetone. 3. Labelling in lactate is consistent with the conversion of acetone into glucose through lactate. 4. There is significant labelling of blood but not rumen volatile fatty acids.

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

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.

STUDIES ON THE METABOLISM OF 1,2-PROPANEDIOL-1-PHOSPHATE

Hanzlik et al. (1) observed the glycogenic action of propylene glycol in rats, and Lindberg (2) has isolated its phosphorylated ester from sea urchin eggs. The latter worker has subsequently demonstrat’ed the presence of 1 ,%propanediol phosphate (PDP) in other t’issues (3). Rudney (4, 5) has suggested that PDP might be an intermediate in the conversion of acetone to “formate” and Cz fragment, while Sakami and Lafaye (6) have suggested that PDP is an intermediate in Ohe metabolism of acetone and a precursor of a 3-carbon compound of the glycolytic cycle. Reports from this laboratory have suggested an alternative pathway of 3-carbon compounds of the glycolytic cycle (7, 8). It appeared to us that PDP might be an intermediate in the alternative pathway suggested by experiments in which slices of heart ventricle anabolizing lactic acid were not inhibited by a concentrat’ion of fluoride sufficient to inhibit enolase. Further, it occurred to us, in view of the recent observations of Harting (9), t,hat PDP might react in the same enzyme systems that normally oxidize cY-glycerophosphate, provided the primary alcohol group is not essential for cr-glycerophosphate dehydrogenase activity. The work reported here demonstrates the oxidation of PDP by a-glycerophosphate dehydrogenase and the removal of the end-product of this oxidation by a further oxidation by addition of a heart muscle extract (10). It has been found that a crystalline preparation of n-glyceraldehyde-3phosphate dehydrogenase will replace the heart’ muscle extract. The data suggest a new series of reactions by which the carbon of PDP might be diverted into pyruvic acid of the glycolytic cycle.

THE METABOLISM OF ACETONE IN THE INTACT RAT

THE METABOLISM OF ACETONE IN THE INTACT RAT