Metabolic interactions between restraint stress and L-lysine: the effect on urea cycle components

We studied the effects of L-lysine on wrap-restraint stress-induced changes in ureagenesis. An exposure to wrap-restraint stress did not affect the plasma concentration of L-lysine, but did decrease plasma urea and arginine. Oral L-lysine (1 g/kg) blocked the effect of stress on ureagenesis, and enhanced the effect of stress on L-arginine. No influence of L-lysine were found in controls. The results imply a stress-specific, ureagenesis-stimulating effect of L-lysine, and suggest an increased requirement for L-arginine during the above conditions.