MODIFICATION OF REPRODUCTIVE FUNCTION IN THE RAT BY 3-METHYLCHOLANTHRENE

Repeated exposure of adult female Wistar rats to 3-methylcholanthrene (MC) (25 mg kg(-1) b.w., i.p., 2xwk, 1 mo) was associated with a signi ficant increase in estrus cycle length. In addition, an increased freq uency of females with constant diestrus and abnormal cycles was observ ed. Young females which had been exposed to MC prepubertally or whose parents had been treated with MC before and during mating also demonst rated cycle prolongation and an increased incidence of constant diestr us and abnormal cycles, These changes in female reproductive function were not associated with measurable changes in plasma sex hormone leve ls. In contrast, MC exposure in adult males was associated with signif icant reductions in circulating plasma testosterone levels, The presen t data also suggest that the offspring of parents who had been exposed repeatedly to MC before and during mating are also affected. Although the central nervous system in offspring of MC-treated parents appeare d to be intact, their oral body temperature was significantly lower. ( C) 1997 The Italian Pharmacological Society.