Effects of dietary pyrazinamide, tryptophan, or nicotinic acid and gamma-ray irradiation on levels of NAD and NADP in various organs of mice.

The effects of large amounts of tryptophan, pyrazinamide, or nicotinic acid in diets on the contents of total NAD (NAD + NADH) and NADP (NADP + NADPH) of various organs were investigated in mice with or without gamma-irradiation. Female C3H/HeN mice were fed one of the following 4 kinds of experimental diets for one week: 1) control diet (20% casein diet containing 3 mg niacin per 100g diet); 2) diet supplemented by 0.5% L-tryptophan (T-diet); 3) diet supplemented by 0.5% L-tryptophan (T-diet); 4) diet supplemented by 0.1% nicotinic acid (NA-diet). Half of the mice in each group were subsequently irradiated with 8 Gy of gamma-ray (60 Co) after 4 h of fasting. Then, the contents of total NAD and NADP in thymus, spleen, kidney, liver, and blood were determined in all animals. The results indicated that NAD content of spleen was higher in PT-group (21.5%) and NA-group (23.2%) than in that of control group. In thymus, however, NAD content of only the PT-group was significantly greater (13.1%) than control. NAD level of kidney was also significantly higher (32.6%) in PT-group. By gamma-irradiation, NAD contents of thymus and spleen of all groups tended to be decreased, but those of kidney and liver were not always reduced. In the latter two organs, significant NAD reduction was shown only in kidney of PT-group and in liver of PT- and NA-groups. Even after irradiation, NAD levels of spleen and thymus in PT- and NA-groups tended to be kept higher than those in irradiated control group.(ABSTRACT TRUNCATED AT 250 WORDS)