Microsomal protein per gram of liver (MPPGL) in paediatric biliary atresia patients.

The microsomal protein per gram of liver (MPPGL) is an important scaling factor in the in vitro-in vivo extrapolation of metabolic data obtained in liver microsomes. This study aimed to determine the MPPGL in four biliary atresia patients (0.6-1.6 years old) undergoing liver transplantation, as it is known that the MPPGL is affected by age and possibly by liver disease. Due to the presence of bilirubin in the homogenates and microsomes, the NADPH-cytochrome reductase activity was used to determine the recovery factor, rather than methods using the dithionite difference spectrum. A mean value of 18.73 (± 2.82) mg/g (geometric mean ± SD, n = 4) was observed, which is lower than the expected MPPGL based on the age of the patients (26.60 ± 0.40 mg/g). This suggests a decreased amount of microsomal protein in the livers of biliary atresia patients. Moreover, no differences in MPPGL between different zones of the liver could be detected.