Repeated dermal toxicity of technical HCH and methyl parathion (50EC) to female rats (Rattus norvigicus).

Repeated dermal application of hexachlorocyclohexane (HCH; 100 mg/kg/day) or methyl parathion (2 mg/kg/day) individually or in combination for 7, 15 and 30 days produced pathomorphological changes in skin, liver, kidney and brain of female rats along with significant enzymatic alterations in the activity of transaminase, alkaline phosphatase lactic dehydrogenase and acetylcholinesterase. The two insecticides in combination though produced severe toxicity on day 30 than at other periods, the changes were not suggestive of any additive or potentiation effect at the test doses.