Effect of ethanol and ethanol-induced hypothermia on protein synthesis in pregnant and fetal rats

The effects of acute and chronic maternal ethanol intake and concomitant hypothermia on in vivo net protein synthesis in maternal and fetal tissues were investigated. No consistent effect on net protein synthesis was found in rats chronically exposed to ethanol if they were tested at a time when blood alcohol levels averaged 0.76 mg/ml and body temperatures were normal (38°C). It rats chronically exposed to ethanol were given ethanol acutely, which raised blood ethanol levels to 3 mg/ml and reduced maternal body temperature by 2.3°C, net protein synthesis was significantly (p < 0.05) reduced in maternal brain and viscera, placenta, and in fetal brain and viscera. Acute ethanol exposure alone, yielding blood levels of 2.7 mg/ml and reducing maternal body temperature by over 2°C, also significantly (p <0.05) reduced net protein synthesis in the same tissues. In both groups of animals hypothermia was then eliminated to assess the effects of ethanol alone on protein synthesis. The ethanol-induced hypothermia was found to be the major contributor to the observed depression in net protein synthesis in maternal brain and heart and in fetal brain. However, at high blood ethanol levels, ethanol directly, independent of hypothermia, also reduced net protein synthesis in maternal kidney, liver, and placenta, and in fetal heart, kidney, and liver. In conclusion, both ethanol-induced hypothermia (to a major degree) and ethanol per se, at blood ethanol levels in excess of 1 mg/ml, depress net protein synthesis in vivo in rats.