DECREASED PLASMA AND TISSUE ISOLEUCINE LEVELS AFTER SIMULATED GASTROINTESTINAL-BLEEDING BY BLOOD GAVAGES IN CHRONIC PORTACAVAL SHUNTED RATS

Background-Previously, arterial concentrations of the essential branch ed chain amino acid isoleucine (Ile) were found to have decreased by m ore than 50% after gastrointestinal haemorrhage in patients and after intragastric blood administration in healthy humans and pigs. Hypothet ically, this induced hypoisoleucinaemia could deplete tissue Ile pools . Aims-To study the effect of repeated blood gavages on arterial and t issue Ile levels during normal and impaired liver funcion. Subjects-Ma le Wistar rats. Methods-14 days after portacaval shunting or sham surg ery, rats received 3 ml bovine erythrocytes or saline at 0, 1, 2, and 3 hours via a gastrostomy catheter in the duodenum. At 0, 2, 4, 6 and 8 hours arterial blood and at 8 hours intestine, liver, muscle, and ce rebral cortex were sampled for determination of ammonia and amino acid concentrations. Results-In both groups repeated blood administration resulted in a marked decrease in plasma Ile (40-60%). This was accompa nied by decreased tissue Ile concentrations in liver (50%), muscle (40 -60%), and cerebral cortex (40-50%), but unaltered intestinal Ile leve ls. In contrast, the arterial and tissue concentrations of ammonia, ur ea, and of most amino acids increased, most strikingly of the other tw o branched chain amino acids, valine and leucine. Conclusions-Simulate d gastrointestinal bleeding by blood gavages in rats with and without impaired liver function leads to hypoisoleucinaemia and decreased tiss ue Ile pools.