title: Purine synthesis de novo and its regulation in rat hepatocytes.
abstract: Purine synthesis de novo and its regulation were studied in freshly isolated hepatocytes from fed adult male rats. The cells incorporated [14C]formate mainly into purine ribonucleotides. The immediate effect of increasing the concentration of inorganic phosphate in the incubation medium was an increase in 5-phosphoribosyl 1-pyrophosphate (PP-ribose-P) availability and a stimulation of purine synthesis de novo. However, prolonged incubation of cells in 25 mM phosphate resulted in a decreased PP-ribose-P availability and purine synthesis de novo. Methylene blue and phenazine methosulfate decreased PP-ribose-P availability and purine synthesis de novo although they stimulated considerably the pentose phosphate pathway. In contrast, epinephrine and glucagon increased significantly PP-ribose-P availability and purine synthesis de novo, but they did not change the activity of the pentose phosphate pathway. These results show a relationship between PP-ribose-P availability and purine synthesis de novo in rat hepatocytes. They emphasize the complexity of the regulation of PP-ribose-P availability.
mesh_terms: D000818:Animals; D005561:Formates / Q000378:metabolism; D005947:Glucose / Q000378:metabolism; D066298:In Vitro Techniques; D007700:Kinetics; D008099:Liver / Q000187:drug effects / Q000378:metabolism*; D008297:Male; D008751:Methylene Blue / Q000494:pharmacology; D008773:Methylphenazonium Methosulfate / Q000494:pharmacology; D010710:Phosphates / Q000494:pharmacology; D010754:Phosphoribosyl Pyrophosphate / Q000378:metabolism; D011687:Purines / Q000096:biosynthesis*; D051381:Rats
chemical_list: D005561:Formates; D010710:Phosphates; D011687:Purines; D008773:Methylphenazonium Methosulfate; D010754:Phosphoribosyl Pyrophosphate; D005947:Glucose; D008751:Methylene Blue