Hormonal Sex

The gonads produce hormones and secrete them directly into the bloodstream. Ova­ries produce two classes of hormones: estrogens (ES-troh-jens) and progestational compounds. Estrogens, the most important of which is estradiol, influence the devel­opment of female physical sex characteristics and help regulate the menstrual cycle. Of the progestational compounds, only progesterone is known to be physiologically impor­tant. It helps to regulate the menstrual cycle and to stimulate development of the uter­ine lining in preparation for pregnancy. The primary hormone products of the testes are androgens (AN-droh-jens). The most important androgen is testosterone, which influences the development of male physical sex characteristics and sexual motivation in both sexes. In both sexes the adrenal glands also secrete sex hormones, including small amounts of estrogen and greater quantities of androgen.