Formula omitted]-[1-13C]Alanine Is a Useful Substance for the Evaluation of Liver Function

Abstract

Background. Using a rat model of hepatectomy, we investigated whether the severity of hepatopathy could be quantitatively measured from changes in expiratory 13CO2 levels after intravenous administration of l-[1-13C]alanine.Materials and Methods. Under nembutal anesthesia, 20 mg/kg l-[1-13C]alanine was administered to rats via the femoral vein, and expiratory 13CO2 levels were measured for 15 min. Then, 30, 70, or 90% hepatectomy was performed. In the control group, simple laparotomy was performed. A breath test was conducted 20 min after laparotomy. We examined the correlation of total 13CO2 output (S) or single point 13CO2 level (SP) every 1 min for 15 min with liver weight/body weight (LW/BW) (%).Results. In the control group, the breath test graph showed a specific peak level about 3 min after administration, but in all groups undergoing hepatectomy, it did not show any peak level during measurement. The correlation coefficient between S12–15 after l-[1-13C]alanine administration and LW/BW was 0.902 (P < 0.0001). The correlation coefficient between SP7 after l-[1-13C]alanine administration and LW/BW was highest, 0.908 (P < 0.0001). The severity of hepatopathy could also be evaluated, with significant differences in S12–14 compared to control when the volume of resected liver was 30% or greater, but there was no significant difference between the groups undergoing 70 and 90% hepatectomy. However, the severity of hepatopathy could be evaluated, with significant differences in S15 and SP7 in all comparisons between groups.Conclusion. In the breath test with intravenously administered l-[1-13C]alanine, the severity of hepatopathy could be quantitatively evaluated in a short period by measuring S15 and SP7.