Bisphenol A (BPA), an environmental estrogen, was given subcutaneously for 4 days to 48 field voles at three doses (10, 50, or 250 mg kg(-1) day(-1)). Plasma sex steroids, thyroxine, weight-regulatory hormones, and liver biotransformation enzymes were determined. There was no mortality in the control group but the mortality in the BPA-exposed animals was significant. BPA increased the plasma testosterone concentrations at 250 mg BPA kg(-1) day(-1). The plasma ghrelin levels measured from pooled plasma increased and at the same time the leptin levels measured from pooled plasma decreased at 50 or 250 mg BPA kg(-1) day(-1). The liver 7-ethoxyrufin-o-deethylase activity decreased slightly at all doses, as did the liver cytosolic glutathione S-transferase activity at 250 mg BPA kg(-1) day(-1). The results show that wild mammals such as the field vole could be more susceptible to BPA than laboratory rodents. More studies on wild mammals are needed to determine the risks of endocrine disruptors in natural ecosystems.
(c) 2002 Elsevier Science (USA)