Hormonal influence on carcinogenicity of methylmercury in mice.

Abstract

The hormonal influence on the carcinogenicity of methylmercury chloride (MMC) was examined in an 80-week experiment using mice. One hundred intact males, 100 intact females, 100 castrated males, and 100 spayed females were divided into 4 groups: (I)intact mice on a basal diet, (II)intact mice on MMC diet, (III)castrated or spayed mice on MMC diet, and (IV)castrated or spayed mice on MMC diet and testosterone propionate (TP) administered s.c. at 0.2 mg/head/week for the entire period. The dietary concentration of MMC was 10 ppm. The survival rate was lowest in both sexes of Group IV because of the aggravation of the toxic nephropathy and the higher incidence of amyloidosis. The incidence of renal epithelial tumors (15/50) and tubular cell hyperplasia (6/50) in Group II males was significantly increased when compared with the controls. No renal tumors or hyperplastic tubules were induced in Group II females or in either sex of Group III. In Group IV, 2 males and 3 females had renal adenocarcinomas and 3 males and 2 females showed tubular cell hyperplasias, indicating some contributing effects of TP. The present results indicate that the testis may have an important role in the induction of renal tumors in mice by MMC.