DDT increases hepatic testosterone metabolism in rats
DDT and its metabolites are considered as endocrine disruptors able to promote hormone-dependent pathologies. We studied the effects of technical-grade DDT on hepatic testosterone metabolism and testosterone hydroxylase activity ratios in the rat. Male and female Wistar rats were treated by gavage with a single dose of technical-grade DDT (0, 0.1, 1, 10, and 100 mg/kg body weight) and killed 24 h later. Hepatic microsomes were incubated with [4-14C]-testosterone and the metabolites were separated by thin-layer chromatography and quantified by radio scanning. DDT increased testosterone biotransformation and modified the profile of metabolites produced in a sex-dependent manner. Males treated with a representative dose (10 mg/kg) produced relatively less androstenedione (AD), 2-hydroxytestosterone (OHT), and 16-OHT but higher 6-OHT whereas treated females produced less 7-OHT and AD but higher 6-OHT and 6-OHT than their respective controls. In both sexes DDT decreased the relative proportion of AD and increased that of 6-OHT suggesting that the androgen-saving pathway was affected. The testosterone 6-/15-OHT ratio, a proposed indicator of demasculinization, was increased in treated males. This effect was in agreement with the demasculinizing ability proposed for DDT. The effects on 6-/16-OHT and 6-dehydrotestosterone/16-OHT ratios followed a similar tendency, with the ratio 6-/16-OHT being the most sensitive marker. Interestingly, these ratios were reduced in treated females suggesting that technical-grade DDT shifted testosterone hydroxylations toward a more masculine pattern. Thus, technical-grade DDT altered the hepatic sexual dimorphism in testosterone metabolism and decreased the metabolic differences between male and female rats.