Technische Universität München

The Entrepreneurial University

In man, acute alcohol ingestion in small amounts may improve erections and increase libido as alcohol has vasodilatory and anxiety-suppressing effects; however, large amounts can cause central sedation, decreased libido and transient erectile dysfunction. Studies have found that moderate or heavy alcohol consumption results in reduced testosterone levels in the blood. In the pituitary gland, alcohol can decrease the production and release of LH and FSH. It has also a direct inhibitory effect on the testosterone secretion by Leydig cells. In addition, alcohol may increase the aromatization of testosterone and androstenedione into estrogens in peripheral tissues. Spermatogenesis is impaired as a result of decreased FSH and testosterone levels, and the direct toxic effect of alcohol or its metabolites on Sertoli cells. Chronic alcoholism may cause feminization, hypogonadism and polyneuropathy, which can additionally affect penile nerve function. Impotence, testicular atrophy, loss of libido, infertility, reduced male secondary sexual characteristics and gynecomastia (as a result of elevated estrogen levels) are observed in almost all chronic male alcoholics.
Acute alcohol ingestion in higher doses can decrease sexual functioning in women by interfering with normal processes of sexual stimulation, and blocking orgasmic response. In a minority of women, moderate alcohol intake has been shown to result in anovulation. In some female heavy drinkers, an increase in the serum prolactin concentration and serum levels of adrenal androgens has been noted. Maternal gestational alcoholism is associated with fetal alcohol syndrome in the baby.
Another alcohol effect on the endocrine function is a decrease of ADH release, leading to water diuresis. Acute ingestion of alcohol may increase serum cortisol in normal subjects. Increased glucocorticoid secretion and pseudo-Cushing’s syndrome have been reported in alcoholics. Acute administration of ethanol to normal subjects results in decrements in serum levels of ionized calcium and parathyroid hormone and augments urinary calcium and magnesium excretion increasing the risk of osteoporosis and fractures in alcoholics. Alcohol by itself may cause hypoglycemia. Alcoholic hypoglycemia can occur in otherwise normal people on an alcohol binge. In patients with alcoholic cirrhosis, reduced peripheral conversion of T4 to T3 and increased aldosterone concentration with fluid retention has also been observed.