Nadp+ biosynthesis by rats receiving a pellagragenic diet

Rats showing signs of pellagra-like disease associated with gelatin ingestion were injected with [14C}-nicotinic acid into the portal vein and the incorporation of the label into hepatic NAD+ and NADP+ was determined. The quantity of NADP+ synthesized within 1 h after [14C]-nicotine acid injection by the experimental group, supplemented or not with dietary niacin, was 75% lower than that synthesized by the control group fed a casein control diet (141nmol h-1 g-1). The NAD+ and NADP+ contents of the liverof the experimental animals were 245 and 93 *g/g liver, respectively, i. e., significantly lower than those for the controls (597 and 210 *g/g liver, respectively). Dietary supplementation with niacin increased the NAD+ content to 317 */g liver but had no statistical effect on NADP+ content (75 *g/g liver) or NADP+ synthesis (46.5 in the free niacin group vs 37.0 nmol h-1 g-1 in the niacin-supplemented group). Therefore, NAD+ content did not seem to limit NADP+ synthesis. These results that the lower availably of NADP+ is responsible, at least in part, for some metabolic derangements in pellagra-like disease, such as a decrease in the activity of NADP+-dependent enzymes observed in quail muscle

The effect of sorbose on NAD(P)ase production by Aspergillus nidulans

NAD(P)ase activity was stimulated when 1% sorbose was present in the culture medium of A. nidulans, and this effect was partially reversed by 1% glucose. 2. The level of extracellular NAD(P)ase was more affected by sorbose in the culture medium than the intracellular enzyme and no morphological changes were obtained. 3. The sorbose effect on NAD(P)ase activity appears to be specific sinle two other exoenzymes tested (ß-glucosidase and alkaline protease) show normal secretion patterns. 4. These findings suggest that the sorbose effect on NAD(P)ase production may be the consequence of metabolic disorders not necessarily linked with the morphological changes induced by the ketohexose