Gonadal and Placental Hormones

The gonads, the testes in males, and the ovaries in females produce gonadal hormones.

Testosterone is the primary male gonadal androgen. It is responsible for the maturation of male reproductive organs, such as the penis and testis, and secondary sexual characteristics, such as facial hair growth and sperm production.

Estrogen and progesterone are two important female gonadal hormones.

Estrogen is responsible for the development of female reproductive organs, such as the uterus and vagina, and secondary sexual characteristics, such as breast development, regulation of the menstrual cycle, and pregnancy maintenance.

Progesterone prepares the uterus for fertilized egg implantation and preserves pregnancy by inhibiting uterine contractions.

During pregnancy, the placenta forms and secretes hormones to ensure the proper growth and development of the fetus.

Placental cells secrete human chorionic gonadotropin, or hCG, which supports the pregnancy during the first trimester.

Another placental hormone called human placental lactogen, or hPL, regulates the mother's metabolism and stimulates breast milk secretion.