Pre- and Postnatal Protein Undernutrition Increases Hepatic Carnitine Palmitoyltransferase I Activity and Decreases Enzyme Sensitivity to Inhibitors in the Suckling Rat

Summary Rats were pair-fed isocaloric diets containing either 25 % (control diet) or 6 % protein (low-protein diet) during the 5 weeks prior to conception and through the gestation and lactation periods; then, carnitine palmitoyltransferase I (CPT-I) activity was determined in liver and skeletal muscle mitochondria isolated from the corresponding pups. Maternal protein undernutrition increased the activity of hepatic CPT-I all along the suckling period, whereas the activity of the skeletal muscle enzyme was unaffected. Moreover, the sensitivity of hepatic CPT-I to inhibition by bothmalonyl-CoA and 4-hydroxyphenylglyoxylate was decreased in the low-protein group. These alterations in the properties of hepatic CPT-I may be involved in the appearance of hyperketonemia in the rat pup upon maternal administration of low-protein diets.