Hepatocytes purine metabolism

The present investigation was undertaken in an attempt to further clarify the effects of fructose on purine nucleotide metabolism. Isolated rat hepatocytes were chosen as a model system, since they allow the study of each pathway of purine metabolism separately and without interference from other tissues. 

Little is known regarding the effect of hormones on purine metabolism. It has been shown that injection of some hormones, such as insulin, glucagon, increase PRPP concentration in mouse liver. Also integrative action of insulin in purine metabolism has been reported. According to these authors, hepatic PRPP amidotransferase activity in diabetic rats decreased 50%, and hepatic concentrations of ATP and GTP decreased markedly. Injection of insulin restored enzyme activity and ribonucleotide level increased. Insulin treatment of rat hepatocytes also increased adenine nucleotide pool3. 

EFFECTS OF FRUCTOSE ON PURINE NUCLEOTIDE METABOLISM IN ISOLATED RAT HEPATOCYTES... 

Fig, 1. - Effect of fructose on isolated rat hepatocyte.s content of ATP, PP-rib-P and Pi, on the rate of de novo purine synthesis (( C) formate incorporation) and on PP-rib-P availability for metabolic reaction (( C) adenine incorporation). The time of incubation indicates the time of incubation with 28mM glucose or fructose before the assay of the specified parameter. The measurement of the rate of incorporation of ( C) formate and of ( C) adenine required additional incubation of 30 min, following the incubation period indicated in the figure. Thus, for these two measurements, 0 time of incubation values refer to values obtained during the 30 min assay incubation period alone (without preincubation). 0 - incubation with glucose o - incubation with fructose. 

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