Hypogonadism
Hypogonadism is a medical term for a defect of the reproductive system which results in lack of function of the gonads (ovaries or testes). The gonads have two functions: to produce hormones (testosterone, estradiol, antimullerian hormone, progesterone, inhibin B), and to produce gametes (eggs or sperm).
The term hypogonadism is usually applied to permanent rather than transient or reversible defects. There are many possible types of hypogonadism and several ways to categorize them.
For example, hypogonadism can be congenital (a condition present at birth) or acquired (a condition which develops in childhood or adult life). An example of congenital hypogonadism is Turner syndrome and an example of acquired hypogonadism is castration.
Hypogonadism can involve just hormone production or just fertility, but most commonly involves both. An example of hypogonadism that often affects fertility far more than hormone production is Klinefelter syndrome. An example of hypogonadism that affects fertility but not hormone production is Kartagener syndrome.
Hypogonadism is most commonly categorized by endocrinologists by the level of the reproductive system which is defective.
Hypogonadism resulting from hypothalamic or pituitary defects is termed secondary hypogonadism or central hypogonadism (referring to the central nervous system). Hypogonadism resulting from defects of the gonads is traditionally referred to as primary hypogonadism.
Physicians measure gonadotropins (LH and FSH) to distinguish primary from secondary hypogonadism. In primary hypogonadism the LH and/or FSH are usually elevated, while in secondary hypogonadism both are normal or low.
Hypogonadism is often discovered during evaluation of delayed puberty, but ordinary delay which eventually results in normal pubertal development and reproductive function is termed constitutional delay.
Hypogonadism is most often treated by replacement of the appropriate hormones (typically testosterone, estrogen, and progestin).
