A gonadotropin-releasing hormone is a hormone that normally originates in the brain’s hypothalamus and signals the pituitary gland to produce follicle-stimulating hormone (FSH) and luteinizing hormone (LH). Follicle-stimulating hormone typically contributes to the maturation of follicles in a female’s ovaries and the maturation of a male’s sperm cells. Luteinizing hormone generally stimulates testosterone secretion in the testes of a male or in a female’s ovaries. In most cases, testosterone produced in the female ovaries is converted to estrogen. LH may also stimulate progesterone secretion in female ovaries.
Gonadotropin-releasing hormone has an important role in the normal process of human reproduction. The triggering of reproductive hormone production by the gonadotropin-releasing hormone often helps men maintain healthy levels of testosterone and produce healthy sperm cells for reproduction. A woman’s reproductive health is generally supported by adequate levels of estrogen and progesterone that are typically maintained by the activity of a gonadotropin-releasing hormone.
Production of gonadotropin-releasing hormone may decrease or increase in response to levels of other hormones in the body. A high level of testosterone, estrogen or progesterone in the bloodstream typically signals the hypothalamus to decrease release of its gonadotropin-stimulating hormone. The reduced level of gonadotropin-releasing hormone usually signals the pituitary gland to decrease its release of follicle stimulating hormone and luteinizing hormone and causes the ovaries or testes to decrease production of the sex hormones. Low blood levels of the reproductive hormones normally cause the hypothalamus to increase production of its gonadotropin-stimulating hormone. Increased gonadotropin-releasing hormone production typically stimulates the pituitary gland to produce more follicle-stimulating hormone and luteinizing hormone—these hormones ultimately cause the testes or ovaries to increase production of their reproductive hormones in most cases.
Some people have medical conditions such as hypogonadism that result in low production of the sex hormones that is typically not corrected by an increase in gonadotropin-releasing hormone. Primary hypogonadism is usually caused by improper functioning of the testes or ovaries and may result from radiation, autoimmune disorders or diseases of the kidney or liver. Genetic disorders such as Turner syndrome or Klinefelter syndrome may also cause hypogonadism. Central hypogonadism is generally caused by problems with the hypothalamus or pituitary gland and may develop from nutritional deficiencies, internal bleeding or infections. Pituitary tumors and genetic disorders such as Kallmann Syndrome can also cause some cases of central hypogonadism.
Hypogonadism in boys may cause growth problems as well as a lack of muscle development and facial hair growth. Some men with this disorder can develop sexual dysfunction, breast enlargement or muscle loss. Girls with hypogonadism may experience reduced growth, no menstruation and a lack of breast development. Hot flashes, low libido and loss of menstruation have occurred in some women with this condition.