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A Brief Introduction to Reproductive Steroid Hormones

 
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Hormones are chemicals that are produced in an organ or gland and then are carried by the blood to another part of the body where they produced a special effect for which they designed (in the target organ). Other hormones are released by organs for local effect most commonly in the digestive tract.

There are several classes of hormones and hormones antagonist:
1) Pituitary Hormones and their Hypothalamic Releasing Factors
2) Thyroid and Antithyroid
3) Estrogens and Progestins
4) Androgens
5) Adenocorticotropic Hormones
6) Insulin, Oral Hypoglycemic Agents
7) Agents Affecting Mineral Ion Homeostasis and Bone Turnover

Among all of those classes of hormones, estrogens, progestins and androgens are belongs to the group of reproductive steroid hormones.

Estrogens

Estrogens are endogenous hormones that produce several physiological actions. In women, promote the development of female secondary sex characteristic, control of ovulation, the cyclical preparation of reproductive tract for fertilization, implantation and nutrition of the early embryo.

Estrogens also have important actions in males, including effects on bone, spermatogenesis, and behavior.

Estrogens compounds

The steroidal estrogens are: estradiol, ethinyl estradiol, estriol, estrone, mestrenol, equilin. There are also a nonsteroidal compounds with estrogenic activity: i.e., diethylstilbestrol, bisphenol, genistein.

Therapeutic uses

The two major uses of estrogens are as:
1) Oral contraceptive;
2) Menopausal Hormone Therapy (MHT), including amelioration of vasomotor symptoms (e.g., hot flushes, sweating, restlessness, insomnia), bone fracture and urogenital atrophy.

Progestins

Progestins or Progestogens are synthetic progesterone with biological activities similar to those of progesterone.

Progesterone is the substance naturally secreted in women’s body by the ovary in the second two weeks of the menstrual cycle.

Progesterone decreases the frequency of gonadotropin releasing hormone (GnRH) pulse, which is the major mechanism of progestin-containing contraceptives. It also influences the endocervical glands, decrease penetration of the cervix by sperm.

Progesterone is important for maintenance of pregnancy, for the development of mammary gland. Progestins have numerous metabolic actions, i.e., increases basal insulin levels, influence lipid profile (increase in LDL), etc..

Progestins compounds

The progestins including the following compounds:
1) Pregnene/pregnadien series: progesterone, medroxyprogesterone acetate (MPA), dydrogesterone
2) Estrane/estrene series: norethindrone(norethisterone), allylestrenol
3) Gonane series: norgestrel, desogestrel, gestodene, drospirenone.

Therapeutic uses

Progestins have 3 principal therapeutic uses:
1) Treatment of luteal deficiency

In non-pregnant women, particularly during perimenopausae and for the treatment of endometriosis and certain functional bleeding.

2. Contraception ( where they are prescribe alone or in combination with estrogens)

Under certain conditions, the intake of progestins alone without estrogens has a contraceptive effect. The progestins used as contraceptive are: norethisterone, lynestrenol, desogestrel, levonorgestrel, medroxyprogesterone acetate (MPA).

3. Treatment of certain tumors

In a very high dose, in women progestins (i.e., MPA) have been used in the treatment for breast cancer, and also for the treatment of prostate cancer in male 

Androgens

Androgen is generic term for any natural or synthetic compound that stimulates or controls the development and maintenance of male characteristics in human (and other vertebrates) by binding to androgen receptors. This includes the activity of the accessory male sex organs and the development of male secondary sex characteristics.

Testosterone is the principal secreted androgen in male. Woman also secreted testosterone, but the magnitude of testosterone secretion is greater in man than in woman at almost all stage of life.

Androgens compound

Besides testosterone, other androgens include:

1) Dehydroepiandrosterone (DHEA)
2) Androstenedione (Andro)
3) Androstenediol, Androsterone
4) Dihydrotestosterone

Therapeutic uses

1) Treatment of testosterone deficiency in man (hypogonadism)
2) Treatment of female hypogonadism (whose serum testosterone level are below normal)
3) Enhancement of athletic performance