Heptachlor and o-p'DDT effects on protein kinase activities associated with human placenta particulate fractions.

Organochlorine pesticides 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 microM were performed. In particulate fractions, total serine/threonine kinase activity was increased by 10 microM HC and o-p' DDT (59% and 82%, respectively). Maximum eightfold increase was observed with 10 microM o-p' DDT on protein kinase A activity. By contrast, protein kinase C activity was reduced by 10 microM HC and o-p' DDT (40% and 52%, respectively). Endogenous substrate phosphorylation studies demonstrated that slight but significant increase in 24-kDa band labeling was produced in nuclear samples with 1, 10, and 100 microM HC and 100 microM o-p' DDT. Exposition to 100 microM HC increased 85-kDa band labeling. In mitochondrial fractions, 10 microM HC and o-p' DDT increased 24- and 65-kDa bands' labeling. 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 signaling pathways.

Time course of brain cholinesterase inhibition and recovery following acute and subacute azinphosmethyl, parathion and carbaryl exposure in the goldfish (Carassius auratus).

Laboratory toxicity data contrasting mortality and brain cholinesterase inhibition in the goldfish (Carassius auratus) are presented. Brain cholinesterase (ChE) was greatly reduced after 96 h of exposure in vivo at sublethal concentrations of azinphosmethyl and parathion. The inhibition of the enzyme was dose dependent, and concentrations higher than 0.1mg/L caused more than 90% inhibition. The effect of carbaryl was less pronounced, achieving an 86% inhibition at concentrations corresponding to the 96-h LC50. After in vivo exposure to sublethal concentrations of parathion and azinphosmethyl (0.1 mg/L) and carbaryl (3.0 mg/L), the activity of the goldfish brain ChE was greatly reduced. In the following 96 h of recovery, the enzyme inhibited with carbaryl was restored to 75% activity, while the enzyme inhibited with organophosphates (OPs) required more than 35 days for recovery. Goldfish were able to withstand high percentages of brain ChE inhibition without mortality, suggesting that another target may be responsible for the lethal effects. However, the enzyme is a good biomarker of acute and subacute exposure to OPs and carbamates.