Effect of Dietary Glycine on the Activities of Serine Dehydratase and Ornithine δ-Aminotransferase in the Liver of Pancreatectomized and/or Hypophysectomized Rats

Abstract

Effects of dietary amino acids on the activities of liver serine dehydratase and ornithine δ-aminotransferase were examined in intact, pancreatectomized, hypophysectomized and hypophysectomized-pancreatectornized rats. Rats were subjected to surgical operations and then force-fed on the 10% casein diet with or without the addition of glycine, arginine and an amino acid mixture for 5 days. Pancreatectomized and hypophysectomized-pancreatecto-mized rats were injected with insulin during the period of force-feeding. More than a half of these rats survived the experimental period in most cases. The activities of serine dehydratase and ornithine δ-aminotransferase were increased 2 to 3 fold by the addition of glycine and the amino acid mixture to the 10% casein diet in intact rats, and such a dietary induction of these enzymes was not affected by insulin. However, the induction of these enzymes by dietary glycine and the amino acid mixture was not observed in pancreatectomized, hypophysectomized and hypophysectomized-pancreatectomized rats. These findings suggest that glucagon and glucocorticoid are involved in the induction of those enzymes by dietary amino acids.