Luteinizing Hormone (LH) Test

Luteinizing hormone (LH) testing measures the concentration of this gonadotropin-releasing protein hormone in the blood serum. It is secreted by the anterior pituitary gland in response to signals from the hypothalamus (gonadotropin-releasing hormone, GnRH). In females, LH stimulates ovulation (the release of a mature egg from the ovary) and transforms the follicle into the corpus luteum, which secretes progesterone. In males, it stimulates the Leydig cells in the testes to produce testosterone. It is a cornerstone in the assessment of the hypothalamic-pituitary-gonadal (HPG) axis.