Nitrogen Balance and Hemoglobin of Adult Rats Fed Amino Acid Diets Low in L- and D-Histidine

Abstract

The nitrogen balance of adult, male Wistar strain rats was adversely affected by severe reduction of histidine in the amino acid mixture that supplied all of the dietary nitrogen. Reduction of histidine resulted in a reduction of hemoglobin of as much as 20%. Certain intakes of histidine which were adequate for the attainment of positive nitrogen balance were inadequate for the maintenance of a normal hemoglobin concentration. It is suggested that histidine requirements are met normally by ingestion; temporary dietary shortages may be made good by the degradation of hemoglobin to supply relatively large quantities of histidine. No obvious difference was noted between the optical isomers of histidine in the maintenance either of nitrogen balance or hemoglobin concentration.