INHIBITION OF VISCERAL PROTEIN-SYNTHESIS BY CERTAIN AMINO-ACID SUPPLEMENTS

This study was focused on the effects produced by diets with different amino acid proportions on visceral protein synthesis (liver and jejun al mucosa). Eight groups of rats received an enteral modular diet supp lemented with different amino acids (Group 1: Ile, Leu, Val; Group 2: Phe, Met, Gly; Group 3: Glu, Arg, Gly; Group 4: Gly, Group 5: Om-Asp, Cys, Pro; Group 6: Lys, Ser, Thr; Group 7: Tyr, His, Ala). Group 8 was the control group. Rats were fed for four days. At the end of this pe riod a flooding dose of C-14-Leu was injected and animals were killed. Liver and jejunal mucosa were removed and protein synthesis rate was determined. Results show a decreased liver protein synthesis in group fed with aromatic amino acids (53.8+/-8.4 vs. 88.6+/-12.1) and Glu-Arg (68.6+/-10.9). In jejunal mucosa there was a decrease of protein synt hesis in groups fed with aromatic amino acids (98.7+/-16 vs 160.5+/-49 ). These changes seem to be related to the intracellular amino acid po ol size and its influence on protein metabolism.