Some Factors Affecting the Passage of Sulphobromophthalein Into and Out of Hepatic Parenchymal Cells

Abstract

Investigations were made on liver slices and on rat livers perfused with Ringer-Locke solution containing sulphobromophthalein. The work of Brauer and Pessotti [1949] on slices was confirmed: the equilibrium set up between the liver slices and the surrounding fluid was only partially due to metabolism of the dye. In perfusion experiments, during the first 20 min., the liver removed almost all the dye from the perfusion fluid: later the concentration of dye in the hepatic vein increased progressively with time. Cooling the liver slowed removal. At constant temperature the liver removed a fixed proportion of the dye presented to it, irrespective of the rate of flow and (within wide limits) of the dye concentration. An equilibrium between the concentrations of dye in the cells and in the sinusoids was demonstrated; the addition of plasma from different animals increased the concentration in the sinusoids, and a species difference in this effect was observed. The dye concentration of transudate coming from the surface of the liver was much higher than that of the outflow at 370 C., but not at 170 C. After a priming dose, sulphobromophthalein was released by the perfused liver, the concentration of dye in the outflow falling exponentially with the same decay constant as the dye within the liver. Bile salts reduced the storage of dye by the liver, but sodium cyanide and sodium fluoride were without effect. The existence of a mechanism for dye concentration in the cells is postulated.SULPHOBROMOPHTHALEIN was first used as an indicator of hepatic function, in 1928, by Rosenthal, but the factors which lead to its disappearance from plasma are only partially understood and the main use of the dye is as a sensitive screening test in the detection of minor degrees of hepatic dysfunction. The usual test consists of injecting 5 mg./kg. body weight intravenously, then estimating the amount of dye left in the circulation 30 min. later by withdrawing a blood sample and measuring the concentration in the plasma. Retention in the plasma of more than 5-10 per cent (the figure varying with different authors) is considered to be evidence of hepatic insufficiency. Because it is important to have an accurate guide to the degree of hepatic failure, much clinical research has been carried out using sulphobromophthalein.Sulphobromophthalein has, however, a much wider application than that of clinical pathology and may be used to investigate the passage of substances through the parenchymal cell membrane. It is bound to the albumin fraction of the plasma protein and is apparently stored by binding to hepatic protein [Andrews and Richards, 1960]. In 1949, Brauer and Pessotti carried out a series of experiments on liver slices and on perfused livers. Their observations, made in vitro, have remained unrelated to experiments carried out in vivo. Using similar methods we have attempted to relate their published data to the whole animal, and in this study we have investigated some of the factors which affect the uptake, storage and release back...

Binding of sulfobromophthalein (BSP) sodium by plasma albumin. Its role in hepatic BSP extraction.

“…Uptake by the slice is appreciably diminished in the presence of protein, however, and they point out that "the magnitude of this effect, as well as the shape of the saturation curves on repetitive transfer [of slices] through protein-free media suggests that the effective dissociation constant of the BSP intracellular protein complex is larger than that of the albumin-BSP complex." Andrews and Del Rio Lozano (22) and Barber-Riley (23) have brought forward evidence supporting this contention. It follows, therefore, that movement of bound BSP into the cells probably cannot be ascribed to a rapid transfer from albumin as a result of greater affinity of, and preferential absorption by, the cellular proteins.…”