Pituitary and thyroid hormones in pregnant alcohol-fed rats and their fetuses

The effect of maternal alcohol consumption on serum and pituitary concentrations of hormones was investigated in pregnant rats and their fetuses. Rats were given 20% ethanol in water prior to pregnancy and 30% ethanol in water throughout gestation, with rat chow ad libitum (alcohol group), or water with an equicaloric diet in which corn starch was substituted for alcohol (pair-fed group), or rat chow and water ad libitum (ad libitum control group). Growth hormone (GH), prolactin (Prl), thyroid-stimulating hormone (TSH), thyroxine (T4), and triiodothyronine (T3) were measured in maternal serum, GH, Prl, and TSH in maternal pituitary, and GH, T4, and T3 in fetal serum. Fetuses of alcohol-fed rats weighed significantly less than fetuses of pair-fed or ad libitum controls. GH, Prl, and TSH were significantly reduced in the maternal serum of alcohol and pair-fed rats compared to ad libitum controls, but T4 and T3 did not differ among the three groups. Pituitary GH was reduced in the alcohol-fed rats, but pituitary Prl and TSH did not differ among the three groups. In the fetuses, neither GH nor T4 differed among the three groups. Fetal T3 was not detectable by this assay. It is suggested that alcohol ingestion affects maternal growth hormone levels, possibly by influencing either the synthesis or the release of the hormone from the pituitary gland. The other hormonal changes may be the result of the reduced food intake, rather than a specific effect of alcohol.