The clearance of bromosulphthalein from plasma as a measure of the changes in hepatic function during pregnancy and lactation in ewes.

Single intravenous injections of bromosulphthalein (BSP) were given to sheep and the change in plasma BSP concentration with time was analysed by computer to obtain the proportionality transfer constants 'a', 'h' and 'b' and plasma volume. The BSP half-time, fractional clearance and retention values were also calculated. Alterations in BSP clearance were compared with changes in bilirubin and liver specific enzyme activities in ewes in late pregnancy and early lactation. The measurement of BSP clearance, particularly the proportionality transfer constants, yielded more information about the alterations in hepatocellular function during pregnancy and lactation than the changes in clinical chemistry. It is suggested that these alterations in liver function are physiological rather than pathological at these times.