Interorgan relationships for glutamine metabolism in normal and acidotic rats

The interorgan relationships for glutamine were investigated in normal, chronically acidotic, and diabetic ketoacidotic rats. In the normal rat, muscle tissue is the major site that releases glutamine into the circulation, and the nonhepatic splanchnic bed (mainly gut) is the major site of glutamine uptake. The liver of normal, postabsorptive rats takes up glutamine also. The kidneys have no significant affect on circulating glutamine in normal rats. In chronic NH4Cl and HCl acidosis, muscle glutamine release doubles. In addition, the liver decreases glutamine uptake and releases glutamine into the circulation. Muscle and liver supply, respectively, about 55 and 45% of the increased glutamine demand of the kidneys during chronic acidosis. No significant changes could be detected in the nonhepatic splanchnic bed during acidosis. In diabetic ketoacidotic rats, the increased demand for glutamine by the kidneys is almost entirely supplied by muscle. No significant changes occur in liver or nonhepatic splanchnic bed.