Abstract
Upon intravenous injection of 1(—)histidine into the dog there is a prompt and long sustained rise in the urea nitrogen of the blood. In contrast to the results with glycine, lysine and arginine, there is but little excretion of unchanged histidine into the urine. Histidine is metabolized slightly faster than arginine as shown by the greater excretion of urea during the 5-hour experimental period. Histidine exhibits a specific dynamic action which is about 50% higher than that shown by arginine, both on the basis of amount administered and amount metabolized. The total increase in heat production is about half as great as that produced by an equal weight of glycine. No toxic effects of histidine were noted.