Studies on the sequence of 2,6-diisopropylnaphthalene metabolite formation using carp hepatocyte

Metabolism of 2,6-diisopropylnaphthalene (2,6-DIPN) was studied in freshly isolated carp hepatocytes with special reference to cytochrome P-450-mediated oxidation. The viability of isolated hepatocytes obtained by use of Ca2+-free and collagenase-containing Hanks buffer was 93%, judging from both trypan blue penetration and lactic dehydrogenase (LDH) leakage. 2,6-DIPN was metabolized to form several oxidized products such as the tertiary hydroxy, the primary hydroxy, and two types of dihydroxy DIPN. From the results of the time course experiments, it was assumed that 2,6-DIPN was hydroxylated primarily on the tertiary and primary positions of the isopropyl group, respectively, and thereafter was converted to tertiary-tertiary and primary-tertiary hydroxylated products. These assumptions are supported by results obtained previously in in vivo and in vitro studies.