Excretion of various phenol red derivatives [phenol red (PSP), bromphenol blue (BPB), and bromcresol green (BCG)] was studied in anesthetized dogs in metabolic acidosis and alkalosis. Similar studies were also made on a phthalein dye, Bromsulphalein (BSP), for comparison. In general, the rate of urinary excretion was greatest in PSP and decreased in BPB, BSP, and BCG in that order; the rate of biliary excretion was greatest in BSP and decreased in the following order; BPB, PSP, and BCG. Although alkalosis slightly augmented the urinary excretion of phenol red derivatives, it lowered the excretion of BSP. It is postulated that this differential rate of urinary excretion of various phenol red derivatives is primarily due to the difference in the rate of tubular secretion rather than that in subsequent reabsorption. The biliary excretion of the dye was practically identical in both acidosis and alkalosis, and this was attributed to the fact that the difference in hepatic bile pH between acidosis and alkalosis was very small. However, the biliary dye excretion was proportional to the rate of bile flow. The gall bladder acidified bile to a similar extent in both acidosis and alkalosis.
Adenosine Triphosphate-Binding Cassette Subfamily C Member 2 Is the Major Transporter of the Hepatobiliary Imaging Agent 99mTc-Mebrofenin