Alcohol activates the sympathetic nervous system, increasing circulating catecholamines from the adrenal medulla. Hypothalamic-pituitary stimulation results in increased circulating cortisol from the adrenal cortex and can, rarely, cause a pseudo-Cushing's syndrome with typical moon-shaped face, truncal obesity, and muscle weakness. Alcoholics with pseudo-Cushing's show many of the biochemical features of Cushing's syndrome, including failure to suppress cortisol with a 48-h low-dose dexamethasone suppression test. However, they may be distinguished by an insulin stress test. In pseudo-Cushing's, the cortisol rises in response to insulin-induced hypoglycemia, but in true Cushing's there is no response to hypoglycemia.
Ethanol affects hypothalamic osmoreceptors, reducing vasopressin release. This increases salt and water excretion from the kidney, causing polyuria. Significant dehydration may result particularly with consumption of spirits containing high concentrations of ethanol and little water. Loss of hypothalamic neurons (which secrete vasopressin) has also been described in chronic alcoholics, suggesting long-term consequences for fluid balance. Plasma atrial natriuretic peptide, increased by alcohol consumption, may also increase diuresis and resultant dehydration.
Alcoholism also affects the hypothalamic-pitui-tary-gonadal axis. These effects are further exacerbated by alcoholic liver disease. There are conflicting data regarding the changes observed. Testosterone is either normal or decreased in men, but it may increase in women. Estradiol is increased in men and women, and it increases as hepatic dysfunction deteriorates. Production of sex hormone-binding globulin is also perturbed by alcohol.
The development of female secondary sexual characteristics in men (e.g., gynaecomastia and tes-ticular atrophy) generally only occurs after the development of cirrhosis. In women, the hormonal changes may reduce libido, disrupt menstruation, or even induce premature menopause. Sexual dysfunction is also common in men with reduced libido and impotence. Fertility may also be reduced, with decreased sperm counts and motility.
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