NAD synthesis from nicotinic acid by the hepatocytes prepared from diabetic rats

Hepatocytes were prepared from rats 3 and 7 days after a single injection of streptozotocin (50 mg/kg) or alloxan (40 mg/kg). Using the hepatocytes, NAD-and total pyridine nucleotide-syntheses from [carboxyl-14C]-nicotinic acid were investigated. The NAD content of streptozotocin- or alloxan-treated hepatocytes was not significantly different from that of the control hepatocytes. Syntheses of NAD and total pyridine nucleotides from nicotinic acid were significantly elevated 3 days after streptozotocin-injection but only total pyridine nucleotide synthesis was significantly higher 7 days after streptozotocin. Only total pyridine nucleotide synthesis was elevated 3 days after alloxan. Differences in the effects of the two diabetogenic agents and the physiological meaning of an increased NAD synthesis from nicotinic acid in the liver of diabetic animals were discussed.