Nacin
when Elvehjem reported the spectacular cure of blacktongue in dogs by means of nicotinic acid, now .own as niacin, the logical supposition was that a niacin ficiency might be the cause of pellagra in humans. Later, Spies, and others demonstrated that most of the classic symptoms of pellagra were relieved by the adminration of niacin. However, most persons suffering from llagra have multiple deficiencies, and it has been found certain symptoms formerly associated with the disse are not relieved until thiamin and riboflavin are pplied along with niacin. Earlier concepts that related :Iagra to a protein deficiency have been clarified by the disovery that one of the amino acids-tryptophan-is a ecursor from which niacin may be synthesized in the animal body.
Nicotinic acid had long been known as a simple ganic compound, but its physiologic properties were realized until it was isolated from potent liver concennes by Elvehjem and associates in 1937.
Two forms of niacin-nicotinic acid and nicotinaimed have antipellagra activity. Therapeutic doeses of nicotinic acid may cause temporary flushing or hot flashes, but nicotinamide does not produce this reaction.
