The effect of dietary nitrite and nitrate on the metabolism of sulphamethazine in the rat

Abstract

1. Rats given 100 p.p.m. of ¹⁴C-sulphamethazine {4-amino-N-(4,6-dimethyl-2-pyrimidinyl)benzene[U-¹⁴C]sulphonamide} in the diet excreted less ¹⁴C-activity in the urine as the amount of nitrite (0 to 1000p.p.m.), but not nitrate (3730 p.p.m.), in the diet was increased.

2. As the level of nitrite, but not nitrate, was increased, there was a concomitant increase in the amount of ¹⁴C-desaminosulphamethazine (4-[(N-4,6-dimethyl-2-pyrimidinyl)benzene-[U-¹⁴C]-sulphonamidein the blood, liver, skeletal muscle and gastrointestinal tract.

3. As the level of nitrite, but not nitrate, supplementation was increased, the amount of methanol-insoluble ¹⁴C-activity in the gastrointestinal tract increased but the amount of insoluble ¹⁴C-activity in the blood, skeletal muscle and liver was not changed.