Hemodynamic effects on oxygen consumption and bile flow in isolated skate liver

A technique is described for perfusion of livers from the little skate, Raja erinacea, in the isolated state at 15 degrees C utilizing a recirculating, well-oxygenated elasmobranch Ringer solution. Bile flow and oxygen consumption were optimal and remained relatively constant over a 4- to 5-h perfusion at portal vein pressures of 2.5-5.0 cm Ringer. At these pressures, bile flow rates were comparable to values previously observed in the free-swimming skate. In contrast to mammalian species, bile secretion in the elasmobranch is particularly sensitive to small changes in perfusion pressure. Hepatic clearance of sulfobromophthalein and [14C]sodium taurocholate demonstrated initial fractional disappearance rates that were also similar to values obtained in vivo. Only small amounts of sulfobromophthalein appeared in bile by 5 h, whereas 78.5 +/- 6.5% of [14C]sodium taurocholate was recovered in bile at this time. These experiments establish portal vein perfusion pressures for study of skate livers in the isolated state in which oxygen consumption is maximal and organic anion clearance from perfusate to bile exceeds values obtained in vivo.