Stimulation by Oestradiol of the Urinary Excretion of Perfluorooctanoic Acid in the Male rat

Abstract

The urinary excretion of perfluorooctanoic acid (PFOA) was studied in male Wistar rats after castration and oestradiol administration as well as in intact females and males. During the first 24 hr females excreted 72 .+-. 5% (N = 6) of a single intraperitoneal dose of PFOA (50 mg/kg) in urine whereas the intact males excreted only 9 .+-. 4% (N = 6). After castration followed by oestradiol administration (500 .mu.g/kg every 2nd day for 14 days), the males excreted PFOA in urine in similar amounts as the females (68 .+-. 14% at 24 hr, N = 10). Oestradiol treatment of non-castrated males produced similar results (61 .+-. 19% at 24 hr, N = 10). Also castration without oestradiol administration significantly enhanced the renal PFOA excretion, but not as effectively as oestradiol treatment. After 96 hr, the concentration of PFOA in serum of intact males was 17-40 times higher than in the serum of other groups. PFOA was similarly bound by the proteins in the serum of females and males. Phase II metabolism of PFOA was not shown either in males or females.