Effect of pesticides on oestradiol-receptor complex formation in rat uterus cytosol.

The effect of gamma-1,2,3,4,5,6-hexachlorocyclohexane (lindane), 2-chloro-4-ethylamino-6-isopropylamino-s-triazine (atrazine) and 2-methylthio-4,6-bis-isopropylamino-s-triazine (prometryne) on the formation of a specific oestradiol-receptor complex in the rat uterus cytosol has been examined in vitro and in vivo. Both in vitro and in vivo, the pesticides significantly (P < 0.001) inhibited the formation of the complex in the rat uterus cytosol. The decrease in the number of free specific binding sites on the receptors was determined. The affinity of binding was not modified under the influence of pesticides, and the Kd value was of the same order of magnitude (10(-9) M). The inhibition was found to be fully non-competitive.