Numerous studies have been made of the excretion of nicotinic acid and its derivatives in the urine, but as yet no satisfactory test has been devised for evaluation of the nutritional status of a person with regard to nicotinic acid. Deficiency is diagnosed on the basis of clinical findings. In view of the importance of nicotinamide in intermediary metabolism, a procedure is needed which will detect mild states of deficiency and indicate the degree of depletion in the tissues. Valuable contributions toward this end have been made by many investigators, including Melnick, Field and their collaborators1 and Perlzweig and his co-workers.2 Recently, Perlzweig, Sarett and Margolis3 suggested that the urinary excretion following the administration of 500 mg. of nicotinamide may serve as a test of nutritional condition in relation to nicotinic acid.
The object of this investigation was to study further the urinary excretion of nicotinic acid