major gonadotropin secreted by the anterior pituitary gland; stimulates gametogenesis and the supporting cells such as the ovarian granulosa cells and the testicular sertoli and leydig cells; FSH consists of two noncovalently linked subunits, alpha and beta; within a species, the alpha subunit is common in the three pituitary glycoprotein hormones (TSH, LH, and FSH), but the beta subunit is unique and confers its biological specificity.