Studies on niacin biosynthesis from 3-hydroxyanthranilic acid in streptozotocin diabetic rats in vivo and in vitro.

Biosynthesis of niacin from 3-hydroxyanthranilic acid (3-OHAA) in normal and streptozotocin diabetic rats was studied in vivo and in vitro. Streptozotocin (SZ) diabetic rats were found to excrete lesser quantities of 3-OHAA, quinolinic acid, niacin and N1-methylnicotinamide (nmn) in their urines following 3-OHAA administration than corresponding normal rats. In vitro studies indicated that SZ diabetic livers form less quinolinic acid from 3-OHAA than normal livers. It appears that this may be due to elevated picolinic carboxylase activity in the livers of SZ diabetic rats.