Modification of malathion induced neurochemical changes by adrenalectomy in rats.

The neurochemical changes induced by malathion, an organophosphate compound, were determined in rats. Maximal changes were found in the brain 2 h after the administration of malathion in a dose of 500 mg/kg ip. The activities of cholinesterase and succinic dehydrogenase were reduced whereas those of glycogen phosphorylase, phosphoglucomutase, and hexokinase were increased; the lactate content of brain was also increase. In malathion treated adrenalectomized animals, changes in the activities of cerebral cholinesterase and succinic dehydrogenase were still present; other changes were, however, abolished by adrenalectomy. Activities of certain enzymes, glucose-6-phosphatase, glucose-6-phosphate dehydrogenase, and lactate dehydrogenase were not significantly altered by malathion in normal or adrenalectomized animals. The results indicate that cerebral cholinergic mechanism in malathion treated animals was not modified by adrenalectomy which, however, abolished or reduced changes in the activities of certain glycolytic and glycogenolytic enzymes that are involved in the utilization or metabolism of glucose. The brain lactate content in malathion treated adrenalectomized animals was, also, not significantly different from the control values, suggesting that modification of induced changes by adrenalectomy.