1-Naphthol conjugation in isolated cells from liver, jejunum, ileum, colon and kidney of the guinea pig

Abstract

Cells from liver, jejunum, ileum, colon and kidney of the guinea pig were freshly prepared by standard isolation procedures. Cells were incubated in the presence of several concentrations of 1(14C)-naphthol, and formation of 1-naphthol glucuronide and 1-naphthol sulphate was assessed at various times by thin layer chromatography. Cells from all five tissues conjugated 1-naphthol. The velocity of conjugation was fastest in jejunals cells (2.9 nmole/mg prot X min) followed by cells from liver, ileum, colon and kidney (0.2 nmole/mg prot X min). The apparent Km-values for glucuronidation ranged from 17 microM to 32 microM, and those for sulphation from 15 microM to 35 microM. Each tissue had a specific conjugation pattern. The two extremes were kidney cells, which had a glucuronidation/sulphation ratio in excess of 10, and colon cells which had a ratio of 0.38. The data suggest that these tissues possess different levels of 1-naphthol-conjugating enzymes, which resemble with regard to their apparent substrate affinities.