Effects of g-hexachlorocyclohexane and L-3,3',5- triiodothyronine on rat liver cytochrome P4502E1- dependent activity and content in relation to microsomal superoxide radical generation
Abstract
Liver microsomal cytochrome P4502E1-dependent p-nitrophenol (PNP) hydroxylation and expression of cytochrome P4502E1 were studied in rats subjected to g-hexachlorocyclohexane (HCCH) or L-3,3,,5-triiodothyronine (T3) administration as a possible mechanism contributing to superoxide radical (O2.-) generation. HCCH treatment (a single dose of 40 mg/kg body wt) produced a 43% increase in the content of total cytochrome P450, whereas T3 (daily doses of 0.1 mg/kg body wt for two consecutive days) led to a 37% decrease. NADPH-dependent O2.- generation was elevated by HCCH and T3, expressed as either per mg of protein or per nmol of cytochrome P450, with a 135% enhancement in the O2.- production/superoxide dismutase (SOD) activity ratios being observed in both conditions. This was partly due to depression of SOD activity. Concomitantly, the molecular activity of NADPH-cytochrome p450 reductase was enhanced by 90 and 69% by HCCH and T3, respectively. In these conditions, microsomal PNP hydroxylation showed increases of 58 and 45% in HCCH- and T3-treated rats over control values, respectively, with a parallel 31% (HCCH) and 41% (T3) enhancement in the content of cytochrome P4502E1 assessed by western immunoblotting. We conclude that HCCH and T3 enhance the expression and activity of cytochrome P4502E1 and that of NADPH-cytochrome P450 reductase in rat liver, regardless of the changes in total cytochrome P450 content, representing major contributory mechanisms to microsomal NADPH-dependent O2.- generation
Más información
Título según SCIELO: | Effects of g-hexachlorocyclohexane and L-3,3',5- triiodothyronine on rat liver cytochrome P4502E1- dependent activity and content in relation to microsomal superoxide radical generation |
Título de la Revista: | BIOLOGICAL RESEARCH |
Volumen: | 36 |
Número: | 3-4 |
Editorial: | SOC BIOLGIA CHILE |
Fecha de publicación: | 2003 |
Página de inicio: | 359 |
Página final: | 365 |
Idioma: | en |
URL: | http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-97602003000300007&lng=en&nrm=iso&tlng=en |
DOI: |
10.4067/S0716-97602003000300007 |
Notas: | SCIELO |