Variation of lead-induced lethality in estradiol-treated mice.

Studies were undertaken to test the female sex hormone beta-estradiol for its ability to modify lethality in young adult female and male mice exposed to lead acetate. Mice were injected with beta-estradiol on d -1 and 0, and immediately after the second injection lead acetate was administered at four subgroup dosages ranging from 75 to 600 mg/kg body weight. Control mice were injected with only lead acetate. On d 4, 6, and 8 after Pb, the median lethal dosages (LD50s) were calculated from the observed mortality ratios by a method of moving averages. LD50 values were considerably lower for the Pb- and beta-estradiol-injected groups than for the controls. Data from these experiments indicate that the beta-estradiol treatments render both female and male mice more vulnerable to the lethal effects of lead acetate.