Drug Metab Dispos. 1984 Nov-Dec;12(6):742-8.  

In vitro metabolism of mono-2-ethylhexyl phthalate by microsomal enzymes.
Similarity to omega- and (omega-1) oxidation of fatty acids.

Albro PW, Chae K, Philpot R, Corbett JT, Schroeder J, Jordan S.

Mono-2-ethylhexyl pthalate (MEHP) is oxidized to omega-, omega-1-, and
omega-2-hydroxylation products as well as (very slightly) to a dicarboxylic acid
by washed microsomes from rat liver and kidney, and rabbit but not rat lung. The
reactions involve molecular oxygen, are strongly inhibited by carbon monoxide
and oxidized cytochrome c, and NADPH is preferred over NADH. Piperonyl butoxide
inhibits hydroxylation of MEHP, but clofibrate does not. The differential
effects of inducers (phenobarbital and clofibrate) and inhibitors (sodium
laurate, n-decane, metyrapone) on terminal and subterminal hydroxylation as well
as differences in apparent Km for the two suggest that rat liver contains at
least two different MEHP hydroxylases. Comparisons of tissue distribution,
susceptibility to inhibitors, and induction properties suggest that the
hydroxylation of MEHP is more likely to be mediated by the P-450 isozymes
associated with omega- and (omega-1)-hydroxylation of fatty acids than with
those that utilize hydrocarbons as substrates.

PMID: 6150824 [PubMed - indexed for MEDLINE]