Abstract
The fractional hepatic extraction (FHE) of histidine absorbed from the in vivo-perfused jejunum was measured in rats with chronic renal failure (CRF) and acute renal failure (ARF). CRF rats were compared with two groups: (a) animals pair-fed with the CRF rats, designated as a protein-calorie malnutrition (PCM) group, and (b) animals fed ad libitum. Despite their poor dietary intake, the FHE of histidine in the CRF animals did not differ from that of rats fed ad libitum. As expected, the PCM animals demonstrated a substantial reduction in the FHE of histidine, thereby making the amino acid more available for peripheral tissue utilization. Animals with ARF also manifested no change in the FHE of histidine. The present study was designed to examine the hypothesis that in CRF, the lack of hepatic adaptation to a diminished intake of histidine may contribute to the abnormal metabolism of this amino acid in uremia.