[Changes in cephalic and peripheral use of glucose and glutamine under the influence of hyperammonemia in rats]

Arterio-venous differences of glucose and glutamine were determined across the brain and across the hind limb in normal and ammonium salt infused rats, before and during an insulin tolerance test, in an attempt to study the effect of hyperammonemia on cephalic and muscular metabolism. The results demonstrate that 1) hyperammonemia reduces the hind limb uptake of glucose without affect the cephalic uptake of glucose which is lowered during hypoglycemia, 2) the reduction of the cephalic and muscular glutamine output induced by the hypoglycemia is masked in presence of an hyperammonemia. In conclusion, it may be assume that, at the concentration obtained in this study, hyperammonemia does not act directly in the pathogenesis of hepatic coma in which a decrease in cerebral glucose uptake described; on the other hand, ammonium plays an important role in the muscle metabolism.