ENZYMES INVOLVED IN GUANINE MONOPHOSPHATE METABOLISM OF AGING CHICKENHEART

The activities qi enzymes involved in GMP metabolism were studied in t he heart si aging chickens, In newborn (1-day-old) animals, GMP breakd own apparently leads to rile final products of purine metabolism, as t he activity qi hypoxanthine-guanine phosphoribosyl-transferase (HGPRT) , the salvage enzyme of GMP is not detectable. On the contrary, HGPRT shows maximal activity in young (20-day-old) chickens, when xanthine o xidase activity is very low, indicating that the metabolic flux conver ges on the salvage pathway. Again, maximal activity of the catabolic e nzymes and a limited resort to the salvage pathway characterize GMP me tabolism of adult (12-month-old) hearts. Finally, in aged (30-month-ol d) chickens, a reduced GMP catabolism and a greater utilization of the salvage pathway might contribute to the maintenance qi rile guanine n ucleotide pool. in conclusion, the pattern of the activities si enzyme s relating to GMP metabolism in the aging heart, compared re, AMP meta bolism, indicates a parallel temporal regulation of tile purine pathwa ys. (C) 1996, Editrice Kurtis