Liver blood flow and blood volume following chronic phenobarbitone administration.

Mlae rats were ra&ndomly divided into 2 groups one of which received 30 mg/kh phenobarbitone for 4 days i.p. and the other sodium chloride. Liver blood flow was measured 24 hr following the last injection of phenobarbitone or sodium chloride using the radioactive colloidal gold clearance technique. In addition, blood volume, liver weight and extraction of radioactive gold were estimated. Following 4 daily infections of phenobarbitone the body weight and the blood volume of both groups were not significantly different. The liver weight in the phenobarbitone treated groups was 27% higher than that found in the control group. Liver blood flow increased from 22.7 ml/min (92,8 ml/min/kg body weight) to 30.1 ml/min (123.7 ml/min/kg body weight). This increase of 33% was highly significant (p less than 0.005). In contrast, the extraction of radioactive gold was 11% lower in the phenobarbitone treated groups than in the controls. The earlier, semiquanititative finding of increased blood flow using a chronic implanted thermocouple could thus be quantified by the present study.