[Change in tryptamine metabolism in vitamin B12 deficiency].

The metabolism of tryptamine was studied in rats in health and in vitamin B12 deficiency. Excretion of cobalamin with urine before and after loading with tryptamine was studied. Daily excretion of tryptamine with urine in vitamin B12-deficient animals was normal or slightly increased. At the same time, the increase in tryptamine excretion with urine in response to tryptophan administration was 2-fold lower in vitamin B12-deficient rats as compared with controls. These data may be interpreted to occur due to a decrease in the rate of tryptamine metabolism in vitamin B12 deficiency in rats. Impairments in metabolism of biogenic amines appear to be involved in the development of neuro-mental diseases accompanied by vitamin B12 deficiency.