Effect of Oral Administration of Streptomycin on Urinary Excretion of B Vitamins in Man

Abstract

The effects of oral administration of streptomycin on the urinary excretion of thiamine, riboflavin, biotin, folic acid, pyridoxine, N¹-methylnicotinamide (N¹-Me) and the 6-pyridone of N¹-Me (pyridone), and on the excretion of nicotinic acid compounds following tryptophan supplements, were studied in 6 subjects maintained for 24 to 44 days on regulated diets. After suitable control periods, streptomycin (calcium chloride complex) was administered orally for 8 to 22 days in doses of 1 gm given either 4 or 6 times daily. Within a few days, fecal cultures showed either complete or partial inhibition of growth of coliform organisms and almost complete absence of the other aerobic organisms studied. The excretion of folic acid was not decreased during streptomycin administration and under certain conditions appeared to be increased. Thiamine and riboflavin excretion were decreased in one subject and not markedly affected in the others. Excretion of pyridoxine compounds was determined in one subject and found to be unaffected by streptomycin. Biotin excretion was markedly decreased during streptomycin administration, and excretion of N¹-Me and pyridone appeared to be slightly reduced. The addition of dl-tryptophan to the control diet led to increases in excretion of quinolinic acid, N¹-Me and pyridone. This conversion of tryptophan to nicotinic acid compounds did not appear to be affected by streptomycin administration and the concomitant change in intestinal flora. This supports the evidence that the main conversion of tryptophan to nicotinic acid takes place in the body, and not in the intestine.