Liver blood flow and enzyme induction in man

An increased liver blood flow in rats and monkeys found following induction of the liver microsomal enzyme system by antipyrine and phenobarbitone, formed the basis of the present study in 7 volunteers. The total body clearance of antipyrine, gamma GT, and the urinary excretion of d-glucaric acid and 6-beta-hydroxycortisol were measured. Liver blood flow was estimated after an overnight fast under basal conditions using the 133Xenon inhalation technique. In addition, liver volume was determined by 7 independent investigations using a 99mTechnetium-sulfur-colloid scan of the liver. Afterwards, each volunteer received 1,000 mg antipyrine daily for 14 days and all measurements were repeated. After antipyrine administration the antipyrine half-life decreased significantly from 12.5 to 7.7 hours with an increase of the antipyrine clearance from 34.1 to 50.8 ml/min. In addition, glucaric acid, gamma-GT and 6-beta-hydroxycortisol were significantly increased. Liver blood flow increased from 36.8 ml/min/100 g to 50.9 ml/min/100 g liver (p less than 0.02). The liver volume showed a tendency to increase but was significantly higher in only three of the seven volunteers investigated. The mean liver volumes of 1483 g before and 1585 g after antipyrine administration were not significantly different. In contrast, total liver blood flow increased significantly from 590 ml/min before to 809 ml/min after enzyme induction (p less than 0.02).