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 branched chain amino acid isoleucine (Ile) were found to have decreased by more than 50% after gastrointestinal haemorrhage in patients and after intragastric blood administration in healthy humans and pigs. Hypothetically, this induced hypoisoleucinaemia could deplete tissue Ile pools.

AIMS

To study the effect of repeated blood gavages on arterial and tissue Ile levels during normal and impaired liver function.

SUBJECTS

Male Wistar rats.

METHODS

14 days after portacaval shunting or sham surgery, 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 cerebral 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 accompanied by decreased tissue Ile concentrations in liver (50%), muscle (40-60%), and cerebral cortex (40-50%), but unaltered intestinal Ile levels. In contrast, the arterial and tissue concentrations of ammonia, urea, and of most amino acids increased, most strikingly of the other two branched chain amino acids, valine and leucine.

CONCLUSIONS

Simulated gastrointestinal bleeding by blood gavages in rats with and without impaired liver function leads to hypoisoleucinaemia and decreased tissue Ile pools.