Altered mineral metabolism: a mechanism underlying the fetal alcohol syndrome in rats.

Excessive ethanol intake during pregnancy can cause birth defects in humans and is referred to as fetal alcohol syndrome (FAS). Because of the characteristic changes that are similar in FAS and zinc (Zn) deficiency, we have examined the role of Zn nutriture in the teratogenicity of ethanol in Sprague-Dawley rats. Female Sprague-Dawley rats were adapted to liquid diets containing Zn at 2 micrograms/ml (LZn), 30 micrograms/ml (AZn), or 300 micrograms/ml (HZn); ethanol contributed either 0% or 36% of kilocalories. Ethanol consumption resulted in reduced fetal growth and retarded skeletal development. Ethanol had no effect on whole body fetal Zn concentrations; however, copper (Cu) deficiency was induced in the HZn fetuses. Ethanol consumption resulted in higher than normal fetal liver CuZnSOD activity in the LZn and AZn groups. Fetuses from HZn dams showed no ethanol effect on CuZnSOD activity, suggesting that the low availability of Cu to the fetus prevented the increase in CuZnSOD activity in response to ethanol. The increase in the activity of fetal CuZnSOD in LZn and AZn groups is consistent with the concept that the metabolism of ethanol results in free radical generation in fetal tissue. Because excessive free radical levels may result in tissue damage, this may be one mechanism contributing to the expression of FAS.