On the problem of a common hepatic transport process for steroids. Uptake of 3-H-taurocholic acid and 3-H-corticosterone into rat liver slices

Abstract

The uptake of 3-H-oubain (2 times 10- minus 9 and 2 times 10- minus 5 M), 3-H-taurocholic acid (2 times 10- minus 8 and 2 times 10- minus M) and 3-H-corticosterone (2 times 10- minus 9 and 2 times 10- minus 5M) into rat liver slices was investiged. The steroids were extensively accumulated as demonstrated by the following T/M ratios: ouabain: 3.82 and 3.72 resp.; taurocholic acid: 10.49 and 9.88 resp.; corticosterone: 12.84 and 8.41 resp.. Only corticosterone uptake was dependent on the medium concentration but without alterations under anaerobic conditions. The contrary could be found in case of ouabain and taurocholic acid. Further differences between the steroids investigated could be shown in experiments on the interaction with organic anions (probenecid, para-aminohippuric acid, citrate and alpha-ketoglutarate). At least no competition among the steroids concerning their uptake into liver tissue could be demonstrated. The results are discussed in contradiction to the current theories concerning the hepatic uptake of steroid compounds.