ABSTRACT
In view of the marked difference between the rat and man in the metabolism of deoxypyridoxine, we examined several other species. The dog, cat, and chicken resemble the rat in producing 4'-deoxypyridoxine-3-sulfate as the major metabolite while the guinea pig, rabbit, pig, and chimpanzee resemble the human in their metabolism of 4'-deoxypyridoxine. The chapter examines metabolism of deoxypyridoxine in vivo, because of the many differences between the effects of deoxypyridoxine compared with those of a dietary B6 deficiency. It finds that the major urinary metabolite of 5'-deoxypyridoxine in the rat was also the 3-sulfate. McCormick and Snell commented that as of 1961, 5'-deoxypyridoxal had not been tested as an antagonist in animals. Thin layer chromatography of tissue homogenates showed that only the gastrointestinal tract and kidney could contain deoxypyridoxine phosphate: pyridoxal phosphate ratios comparable to those required to produce enzyme inhibition in vitro.
