Alcohol's effects on male reproduction

Abstract

The male reproductive system consists of the hypothalamus, the anterior pituitary gland, and the testes. Alcohol can interfere with the function of each of these components, thereby causing impotence, infertility, and reduced male secondary sexual characteristics. In the testes, alcohol can adversely affect the Leydig cells, which produce and secrete the hormone testosterone. Studies found that heavy alcohol consumption results in reduced testosterone levels in the blood. Alcohol also impairs the function of the testicular Sertoli cells that play an important role in sperm maturation. In the pituitary gland, alcohol can decrease the production, release, and/or activity of two hormones with critical reproductive functions, luteinizing hormone and follicle-stimulating hormone. Finally, alcohol can interfere with hormone production in the hypothalamus.

Components of the hypothalamic-pituitary-gonadal axis. The hypothalamus releases gonadotropin-releasing hormone (GnRH) to the anterior pituitary gland, which in turn releases luteinizing hormone (LH) and follicle-stimulating hormone (FSH) into the bloodstream. LH and FSH circulate to the testes, which release testosterone in response. When testosterone levels in the blood rise, the anterior pituitary becomes less responsive to GnRH stimulation; as a result, both LH and FSH secretion diminish and testosterone levels fall. This process is called a negative feedback mechanism. Likewise, when testosterone production declines, the anterior pituitary becomes more responsive to GnRH and increases its release of LH and FSH, thereby stimulating testosterone production. NOTE: ⊕ excites; ⊝ inhibits. Testosterone may also have a negative feedback effect on GnRH.