Luteinizing Hormone (LH)
A pituitary hormone that stimulates the gonads. In the man, LH is necessary for spermatogenesis (Sertoli cell function) and for the production of testosterone (Leydig cell function). In the woman, LH is necessary for the production of estrogen. When estrogen reaches a critical peak, the pituitary releases a surge of LH (the LH spike), which releases the egg from the follicle.