Intravenous L-alanine tolerance test: A sensitive tool for evaluating functional capacity of the cirrhotic liver

Since alanine induced glycemic response can be interpreted as an exellent index of hepatic gluconeogenesis, functional capacity of the liver was tested by means of the 30 minutes' intravenous infusion of 300ml of 10% L-alanine solution in fasted state to 17 patients with cirrhosis of the liver (8 compensated and 9 decompensated cirrhotics) and 6 controls. In compensated cirrhotics, maximum glycemic response to alanine was not significantly different from that of controls at the end of the infusion. By contrast, there was no glycemic response to alanine in decompensated cirrhosis. In fact, blood glucose level was even decreased from the pre-infusion level. Blood lactate level after alanine infusion was significantly higher in decompensated cirrhosis when compared to the controls. Furthermore, in decompensated cirrhosis, blood alanine levels remained elevated even at 120 minutes after the end of the infusion. Moreover the degree of alanine-induced glycemic response was closely related with that of the dye (ICG) retention. In conclusion, alanine-induced glycemic response provides a sensitive tool for evaluating the fuctional capacity of the cirrhotic liver.