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Fetal and Maternal Thyroid Hormone Responses to Ethanol Exposure During the Third Trimester Equivalent of Gestation in Sheep
Author(s) -
Cudd Timothy A.,
Chen WeiJung A.,
West James R.
Publication year - 2002
Publication title -
alcoholism: clinical and experimental research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.267
H-Index - 153
eISSN - 1530-0277
pISSN - 0145-6008
DOI - 10.1111/j.1530-0277.2002.tb02431.x
Subject(s) - fetus , gestation , thyroid , pregnancy , endocrinology , fetal alcohol syndrome , hormone , thyroid function , medicine , triiodothyronine , ethanol , thyroid function tests , physiology , biology , biochemistry , genetics
Background: Abnormal thyroid hormone system function in the mother or fetus during pregnancy can result in brain defects, some of which resemble those found in children with fetal alcohol syndrome. It has been hypothesized that ethanol may act to mediate alcohol‐related birth defects in part by altering thyroid hormone system function. We investigated whether a binge pattern of maternal ethanol consumption over the last trimester equivalent of gestation in sheep results in an alteration in fetal or maternal thyroid function. Methods: Pregnant ewes received saline or ethanol beginning on day 109 of gestation (term, 145 days) for three consecutive days per week followed by 4 days without exposure. The fetuses were surgically instrumented on day 113, and experiments were performed on days 118 or 132. Fetal and maternal blood samples were collected, and plasma tri‐iodothyronine (T 3 ), thyroxine (T 4 ), and free T 4 concentrations were measured. Results: Fetal T 3 and T 4 on day 118, fetal T 3 on day 132, and maternal T 3 on day 132 were lower in response to ethanol. Fetal and maternal free T 4 and maternal T 4 did not change in response to ethanol. Fetal thymus and adrenal weights were reduced in response to ethanol. Conclusions: We conclude that, in sheep, maternal ethanol exposure during the third trimester equivalent resulting in blood ethanol concentrations that are commonly achieved by ethanol abusers decreases circulating thyroid hormone concentrations in the mother and fetus and fetal thyroid and thymus mass.