Part of “CHAPTER 16 – PITUITARY GONADOTROPINS AND THEIR DISORDERS“

Many pituitary adenomas, previously classified as nonfunctional, produce gonadotropins or their subunits.79 Indeed, as many as 40% to 50% of all macroadenomas may originate in gonadotropes.80 These tumors (Table 16-2) are generally recognized because of mass effects, such as visual impairment, headache, or the findings of sellar enlargement and pituitary mass on radiologic examination. The gonadotropins and their subunits that are produced only uncommonly lead to a clinical syndrome, partly explaining why these tumors were previously thought to be non-functional. Gonadotropin subunits have no known bioeffects, and the intact hormones are rarely produced in sufficient amount to cause a clinical syndrome. In fact, paradoxically, deficiencies of pituitary hormone secretion, especially of LH, are more commonly found, because the tumor mass compresses the normal pituitary, thereby impairing normal hormone production.