Plasma glucose and protein concentrations in rat fetuses and neonates exposed to cataractogenic doses of mirex.

Mirex was administered to rats during gestation or the early postnatal period and the effects on blood chemistry were studied, especially with regard to changes which might play a role in the known cataractogenicity of mirex. In the prenatal study dams were intubated with 6 mg/kg/day mirex on Days 8 through 15 of gestation, and fetal blood samples were obtained on Days 18 and 20. For postnatal studies, litters were culled to eight pups at birth. Dams were intubated with 10 mg/kg/day mirex on Days 1 through 4 postpartum, and blood was drawn from pups at ages 6 through 14 days. Glucose determinations were done on a Beckman ASTRA 8 autoanalyzer. Protein determinations were done by the method of Lowry et al. (O.H. Lowry, N. J. Rosebrough , A. L. Farr, and R. J. Randall (1951). J. Biol. Chem. 193, 165-175.) Plasma glucose levels were decreased by over 40% in mirex-treated fetuses which developed cataracts. Postnatal exposure to mirex did not alter plasma glucose. Mean plasma protein concentrations were significantly lower in treated litters on Days 12 and 14 postpartum, and treated pups with cataracts on Day 14 were hypoproteinemic compared to treated pups without cataracts. Hypoproteinemia is a common factor related to cataractogenesis induced by either prenatal or postnatal mirex exposure, and may possibly be a causative factor. Although hypoglycemia may be a contributing factor in prenatal cataractogenesis, it does not seem to be implicated in postnatal cataractogenesis.