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Progesterone

Progesterone is a hormone produced by both women and men, although to a lesser extent in men, and is an important precursor in the biosynthesis of other hormones in the human body. Progesterone is the active, natural progestin secreted by the ovary, mainly from the corpus luteum, from the placenta, and from the adrenal cortex. Progesterone released during the luteal phase of the normal female cycle leads to development of a secretary endometrium. Progesterone is a major precursor in the biosynthesis of most other steroids, particularly glucocortoids, androgens and estrogens. After ovulation, the follicle becomes the corpus luteum, which is the primary source of endogenous progesterone. Progesterone converts estrogen primed proliferating endometrial cells of the uterus into mature secretory cells. During this conversion, mature endometrial cells and glands are produced, along with blood vessels and carbohydrates necessary to support a fertilized ovum if conception occurs. If conception does not occur, the corpus luteum regresses and progesterone production decreases. This leads to necrosis of the endometrial cells and glands with sloughing of the epithelial layer of the endometrium. Progesterone also stimulates the growth of the uterus and a number of specific changes in the endometrium and myometrium. It is essential for the development of decidual tissue and the differentiation of luminal and glandular epithelial tissue. Progesterone also plays several roles in gestation, including breast enlargement, inhibition of uterine contractility, maintenance of gestation, immunological protection of the embryo, and inhibition of prostaglandin synthesis. Progesterone influences the endocervical glands, and progesterone is very important for the maintenance of pregnancy as progesterone suppresses menstruation and uterine contractility. Progesterone has application in the management of ovarian disorders, in dysfunctional irregular menstrual cycles, in dysmenorrhea, in premenstrual and post menopausal symptoms, especially in the latter where menopause is an endocrine deficiency state. Progesterone has been used pharmaceutically in the treatment of a number of clinical disorders such as luteal phase deficiency, dysfunctional uterine bleeding, endometriosis, endometrial carcinoma, benign breast disease, pre-eclampsia, and assisting in vitro fertilization, preventing early abortion and reducing the occurrence of endometrial hyperplasia in estrogen replacement therapy (ERT). The use of natural progesterone has been linked to the relief of hot flashes, mood swings, bloating, loss of libido, vaginal dryness, and other uncomfortable symptoms associated with menopause and pre-menstrual syndrome (PMS). It is also useful in counteracting the damaging effects of estrogen dominance. Natural progesterone attaches to and blocks the receptors for estrogen molecules and estrogen-like compounds, causing them to travel through the body and eventually to be metabolized and excreted in urine. Natural progesterone also has been shown to alleviate, prevent, or even actually reverse osteoporosis. Natural progesterone is a hormone which, in women, is synthesized mainly by the ovary and, to a lesser degree, by the adrenal glands and the placenta during the second part of pregnancy. Non endocrine synthesis of progesterone, particularly at the level of neurones, is also possible. Insufficient progesterone secretion in a woman may lead to various disorders, in particular premenstrual syndromes, menstrual irregularities through disovulation or anovulation, benign mastopathies, premenopause, and menopause.

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