Human Sexuality: The Sex Hormones

Progesterone

A female hormone secreted by the ovaries. It helps to prepare the lining of the uterus for the implantation of fertilized ovum, to stimulate milk production in the breasts, and to maintain the placenta. It works in conjunction with estrogen to prepare the female system for pregnancy.

Estrogens

A group of hormones that control female sexual development. It controls development of the female sex organs, the menstrual cycle, parts of pregnancy, and secondary sex characteristics such as breast development. The ovaries produce most of it in women, although the adrenal glands and the placenta also produce small amounts. Men also produce a small amount of it in the testes.

Androgens

A group of hormones that control male sexual development and include testosterone. They stimulate the development of male sex organs and secondary sex characteristics such as beard growth and a deepening voice. Testosterone also plays an important part in stimulating sexual desire and is secreted by the testes in men and the ovaries in women. A small amount is also produced by the adrenal glands in both men and women.

Inhibin

A hormone produced by the cells of the testes that signals the anterior pituitary to decrease FSH production if the sperm count gets too high.

Follicle-Stimulating Hormones (FSH)

A hormone released by the pituitary gland that stimulates the follicular development in females and the formation of sperm in males.

Luteinizing Hormone (LH)

A hormone released by the pituitary gland the stimulates ovulation and the release of other hormones, notably progesterone in the female and testosterone in the male. It also stimulates the cells in the testes to produce testosterone.

Gonadtropin-Releasing Hormone (GnRH)

A hormone that effects the nervous system. It is produced in the hypothalamus of the brain. It means "gonad stimulating," and it stimulates the release of hormones, which induce the ovaries and testes (as well as other glands) to secrete hormones.

Oxytocin

A pituitary hormone that stimulates ejection of milk from the breasts and causes increased contractions of the uterus during labor.

Prolactin

A pituitary hormone that stimulates milk production after childbirth and also the production of progesterone.