Stimulation by paraquat of microsomal and cytochrome P-450-dependent oxidation of glycerol to formaldehyde.

Glycerol can be oxidized to formaldehyde by microsomes in a reaction that is dependent on cytochrome P-450. An oxidant derived from the interaction of H2O2 with iron was responsible for oxidizing the glycerol, with P-450 suggested to be necessary to produce H2O2 and reduce non-haem iron. The effect of paraquat on formaldehyde production from glycerol and whether paraquat could replace P-450 in supporting this reaction were studied.

Structural determinants for alcohol substrates to be oxidized to formaldehyde by rat liver microsomes.

Glycerol can be oxidized to formaldehyde by rat liver microsomes and by cytochrome P450. The ability of other alcohols to be oxidized to formaldehyde was determined to evaluate the structural determinants of the alcohol which eventually lead to this production of formaldehyde. Monohydroxylated alcohols such as 1- or 2-propanol did not produce formaldehyde when incubated with NADPH and microsomes.

Role of cytochrome P450 in the oxidation of glycerol by reconstituted systems and microsomes.

Glycerol can be oxidized by rat liver microsomes to formaldehyde in a reaction that requires the production of reactive oxygen intermediates. Studies with inhibitors, antibodies, and reconstituted systems with purified cytochrome P4502E1 were carried out to evaluate whether P450 was required for glycerol oxidation. A purified system containing phospholipid, NADPH-cytochrome P450 reductase, P4502E1, and NADPH oxidized glycerol to formaldehyde.

Role of iron, hydrogen peroxide and reactive oxygen species in microsomal oxidation of glycerol to formaldehyde.

Rat liver microsomes can oxidize glycerol to formaldehyde. This oxidation is sensitive to catalase and glutathione plus glutathione peroxidase, suggesting a requirement for H2O2 in the overall pathway of glycerol oxidation. Hydrogen peroxide can not replace NADPH in supporting glycerol oxidation; however, added H2O2 increased the NADPH-dependent rate.

Rapid decrease of cytochrome P-450IIE1 in primary hepatocyte culture and its maintenance by added 4-methylpyrazole.

Studies were conducted to evaluate the possible induction or the maintenance of cytochrome P-450IIE1 in primary hepatocyte cultures by the inducing agent 4-methylpyrazole. Hepatocytes were isolated from control (noninduced) rats and from rats treated in vivo with either pyrazole or 4-methylpyrazole to induce P-450IIE1. The content of P-450IIE1 was determined by Western blots with antipyrazole P-450 IgG, and catalytic activity was assessed by assays of dimethylnitrosamine demethylase activity.