Influence of liver size on the relationship between in vivo and in vitro studies of drug metabolism

One hundred and twelve subjects were investigated to elucidate the influence of liver size on the relationship between in vivo (antipyrine kinetics) and in vitro (cytochrome P-450) studies of drug metabolism. The correlation between these variables appeared to be linear in 20 subjects with normal parenchyma and nonlinear in 92 subjects with slight or severe histological alterations in liver biopsy specimens. When liver size was taken into account by calculating the total amount of cytochrome P-450/liver (liver weight g x cytochrome P-450 concentration nmol/g), the relationship between in vivo and vitro studies improved in normal controls. In subjects with changed liver structure the correlation showed no improvement and remained nonlinear.