Comparative study of 8-monohydromirex and mirex toxicity in male rats

Abstract

Male rats were fed 0, 0.5, 5.0, 50, and 75 ppm mirex or 8-monohydromirex for 28 days. There were no consistent differences between weight gain of treated or control groups. There were significant increases in LW/BW in the 5, 50, and 75 ppm mirex and 8-monohydromirex treatment groups. Serum β-glucuronidase was elevated in the 0.5, 50, and 75 ppm mirex treated groups, and was elevated in the 5, 50, and 75 ppm 8-monohydromirex treated groups. There were no consistent changes in serum sorbitol dehydrogenase in any treatment group, but there were significant increases in liver sorbitol dehydrogenase at all levels for both toxicants. Hepatic microsomal parameters were induced by both compounds. No consistent toxic effects resulting from mirex or 8-monohydromirex treatment were indicated by serum glucose, protein, and cholesterol or by selected hematological factors. The histological changes observed in the livers of animals treated with mirex and 8-monohydromirex included cell swelling with increased cytoplasmic density; a dense homogenous region centered around the nuclear area; hyaline or myelin-like cytoplasmic inclusions appearing in some tissue sections of the highest treatment levels; and lipidosis. Histological changes in testes of treated rats were less obvious than lesions observed in the liver. There was a loss of staining intensity of the seminiferous tubules associated with hypocellularity of the tubules. Decreased spermatogenesis was evident in three rats from the high dose groups. Both compounds produced detectable histological changes in the thyroid glands at the 75 ppm treatment level. There did not appear to be any consistently significant differences between the toxic effects, either qualitative or quantitative, of mirex and 8-monohydromirex in rats fed either compound for 28 days.