The effect of o,p'-DDT feeding and food deprivation on plasma and liver amino acids and liver serine dehydratase in rats

The effect of DDT feeding and food deprivation on liver and plasma amino acid concentrations was studied. DDT feeding had no effect on plasma amino acids but resulted in an increase in the concentration of liver isoleucine, ornithine, phenylalanine, serine, and threonine. In rats that were fed the control or DDT for 2 weeks and then deprived of food for 48 hr, the concentrations of liver isoleucine, phenylalanine, serine, and threonine were similar. The activity of liver serine dehydratase was decreased in hepatocytes from DDT-fed rats compared to fed controls. After food deprivation, the activity of serine dehydratase was similar in hepatocytes from control and DDT-fed rats, which is consistent with the response of liver serine and threonine concentrations to DDT feeding. Gluconeogenesis from serine was determined in isolated hepatocytes from DDT and control-fed rats and it was found that rates of gluconeogenesis were not affected by DDT feeding. This would indicate that the activity of serine dehydratase is not limiting for gluconeogenesis from serine in hepatocytes from fed rats.