Common properties of hepatocellular uptake of cholate, iodipamide and antamanide, as distinct from the uptake of bromosulfophthalein.

The uptake of iodipamide and of the cyclopeptide antamanide by isolated hepatocytes was reduced reversibly in the absence of oxygen as recently shown for the transport of cholate. Oligomycin, antimycin A and carbonylcyano-chlorophenylhydrazone (CCCP) completely blocked the uptake of iodipamide and antamanide whereas the uptake of cholate was only partially decreased. Reduction of ATP in hepatocytes following replacement of glucose by fructose inhibited the uptake of iodipamide, of antamanide, and also of cholate. In contrast, the penetration of bromosulfophthalein remained unaffected under the above conditions. Arrhenius paralysis yielded high apparent activation energies for the uptake of cholate, iodipamide, and antamanide being 89, 77 and 55 kJ/mol respectively but only 22 kJ/mol for bromosulfophthalein. Mutual transport inhibition was found for iodipamide, antamanide and cholate as well as for bromosulfophthalein. Cholate inhibited the uptake of iodipamide and antamanide competitively. In contrast, bromosulfophthalein inhibited iodipamide uptake in a mixed order fashion. The results suggest a common uptake mechanism for cholate, iodipamide and antamanide different from that of bromosulfophthalein.