(+)-Propranolol clearance, an estimation of hepatic blood flow in man

1 Hepatic blood flow was determined before and during (+)- and (+/-)-propranolol plasma concentration plateaus in 19 patients with suspected renal hypertension and normal liver function. 2 Hepatic blood flow significantly decreased (P less than 0.001) during (+/-)-propranolol administration and remained unchanged during (+)-propranolol administration. 3 Hepatic extraction ratio was 74 +/- 1% (+/-)-propranolol and 79 +/- 2% for (+)-propranolol. 4 Total propranolol clearances were determined during the steady-state achieved by a constant infusion. A highly significant positive relationship was observed (r = +0.86; P less than 0.01) between hepatic blood flow and (+)-propranolol clearance. The slope of the curve was 1.05 +/- 0.27. 5 The result implies that the total clearance of (+)-propranolol constitutes an accurate estimation of basal hepatic blood flow in subjects with normal liver function.