Monoamine oxidase activities in tissues of thiamine-deficient rats

Abstract

The oxidation of monoamine by homogenates of tissues of thiamine-deficient rats was measured with noradrenaline as substrate. Monoamine oxidase activities were depressed in tissues in which the catecholamine content had previously been found raised during thiamine deficiency, with the exception in the cerebral cortex. The impaired enzyme activities were restored to the control level by repeated thiamine injections. An accumulation of pyruvic acid did not inhibit monoamine oxidase activity and thiamine pyrophosphate is not implicated as a co-factor in the oxidation of monoamine substrate.