Hypogonadism in Men and Women

Abstract

The gonads in both sexes serve the same dual functions, namely, the production of gametes and sex steroids. These functions are clinically quiescent in children but subsequently are induced at puberty and then maintained through much of adulthood by the glycoprotein pituitary gonadotropins leutinizing hormone (LH) and follicle-stimulating hormone (FSH). By historical convention these names refer to events and structures within the ovary, but their structures are identical in both men and women and their functions in each gender are largely similar. The secretions of these gonadotropins are largely regulated by classic feedback inhibition from circulating gonadal products, with LH being excreted by the sex steroid levels in blood and FSH by proteins (inhibins) produced by developing gametes (Fig. 1). When inadequate gonadal function results from a defect within the gonad itself, the condition is referred to as primary gonadal failure. Hypogonadism resulting from pituitary or hypothalamic defects is referred to as secondary and tertiary gonadal failure, respectively. Despite the later distinction, many authors continue to refer to either pituitary or hypothalamic failure as secondary or “central” hypogonadism.