Drugs and Pituitary Function

Publisher Summary Many drugs, both therapeutic and recreational, alter the function of the pituitary gland, usually as a side effect unrelated to the primary indication for which the drug was given. Consumption of beverages containing ethanol may alter pituitary function in several ways: by direct effects on the brain or pituitary gland; by altering the function of end organs (e.g., testis) and provoking feedback-mediated changes in pituitary hormone secretion; and by modifying the peripheral metabolism or action of hormones with resulting effects on pituitary function. In some studies, the acute administration of ethanol has been reported to stimulate adrenocorticotropic hormone (ACTH) and cortisol secretion. Cigarette smoking results in the acute release of several pituitary hormones, and the effects appear to be due to nicotine. Several studies have reported increases in plasma cortisol, DHEA, ACTH and bendorphin/ β-lipotropin in response to smoking one or more medium- or high-nicotine cigarettes; sham smoking or smoking low-nicotine cigarettes had no such effect. Acute administration of opiates (e.g., morphine, heroin, codeine, fentanyl, β-endorphin, enkephalins) has profound and generally consistent effects on human pituitary function. In males, serum LH is lowered, followed by a fall in serum testosterone. In females, opiates suppress serum LH in premenopausal subjects, often resulting in irregular menses or amenorrhea. Effects of various other substances and hormones are discussed in this chapter.