Prenatal alcohol exposure and fetal programming: effects on neuroendocrine and immune function

Alcohol abuse is known to result in clinical abnormalities of endocrine function and neuroendocrine regulation. However, most studies have been conducted on males. Only recently have studies begun to investigate the influence of alcohol on endocrine function in females and, more specifically, endocrine function during pregnancy. Alcohol-induced endocrine imbalances may contribute to the etiology of fetal alcohol syndrome. Alcohol crosses the placenta and can directly affect developing fetal cells and tissues. Alcohol-induced changes in maternal endocrine function can disrupt maternal-fetal hormonal interactions and affect the female's ability to maintain a successful pregnancy, thus indirectly affecting the fetus. In this review, we focus on the adverse effects of prenatal alcohol exposure on neuroendocrine and immune function, with particular emphasis on the hypothalamic-pituitary-adrenal (HPA) axis and the concept of fetal programming. The HPA axis is highly susceptible to programming during fetal development. Early environmental experiences, including exposure to alcohol, can reprogram the HPA axis such that HPA tone is increased throughout life. We present data that demonstrate that maternal alcohol consumption increases HPA activity in both the maternal female and the offspring. Increased exposure to endogenous glucocorticoids throughout the lifespan can alter behavioral and physiologic responsiveness and increase vulnerability to illnesses or disorders later in life. Alterations in immune function may be one of the long-term consequences of fetal HPA programming. We discuss studies that demonstrate the adverse effects of alcohol on immune competence and the increased vulnerability of ethanol-exposed offspring to the immunosuppressive effects of stress. Fetal programming of HPA activity may underlie some of the long-term behavioral, cognitive, and immune deficits that are observed following prenatal alcohol exposure.