Heptachlor and o-p' DDT Effects on Protein Kinase Activities Associated with Human Placenta Particulate Fractions

MAGNARELLI, GLADIS; SOUZA, MARÍA SOL; PECHEN DE DANGELO, ANA MARÍA

Journal of Biochemical and Molecular Toxicology

Wiley

Lugar: DOI 10.1002/jbt.20277; Año: 2008 p. 185 - 192

ABSTRACT Organochlorine pesticides (OC) have been detected in placenta. The ability of heptachlor (HC) and 1, 1, 1- tricholoro-2-(2-chlorophenyl)-2-4- chlorophenyl) ethane (o-p’ DDT) to interfere with protein phosphorylation was evaluated. In vitro incubations of cell-free placental villi homogenates with a concentration range 1- 100 μM were performed. In particulate fractions, total serine/threonine kinase activity was increased by 10 μM HC and o-p’ DDT (59 and 82 % respectively). Maximum 8-fold increase was observed with 10 μM o-p’ DDT on protein kinase A (PKA) activity. By contrast, protein kinase C (PKC) activity was reduced by 10 μM HC and o-p’ DDT (40 and 52 %, respectively). Endogenous substrate phosphorylation studies demonstrated that slight but significant increase in 24 kDa band labelling was produced in nuclear samples with 1, 10 and 100 μM HC and 100 μM o-p’ DDT. Exposition to 100 μM HC increased 85 kDa band labelling. In mitochondrial fractions, 10 μM HC and o-p’ DDT increased 24 and 65 kDa bands labelling. These data indicate that both pesticides affect protein kinase activities in particulate fraction. Nuclear compartmentalization of these compounds, insertion in membranes and chemical stress production may be associated to the observed effects, thus suggesting deleterious consequences in signalling pathways.