Clearance of bromosulphthalein by the liver of sheep

The application of a serial sampling technique for assessing bromosulphthalein (BSP) clearance by the liver of sheep is described. After a single intravenous injection BSP was almost completely cleared by the liver into the bile. Clearance by the liver was in two phases which allowed the calculation of the proportionality transfer constants a (from plasma to liver), h (from liver to bile) and b (from liver back to plasma). The ratio of a:h was approximately 4:1 in sheep. The proportionality transfer constants had the advantage over fractional clearance and retention tests of relating the test more precisely to the condition of the liver at the cellular level. The single injection method was simple, non-invasive and repeatable and suitable for conscious animals.