Estrogen and Progestins Overview

Study Notes

Gonadal Hormones

Gonadal hormones include estrogen, progesterone, and testosterone.
Natural estrogens comprise Estradiol, Estrone, and Estriol.
Synthetic steroids include Ethinyl Estradiol and Mestranol.
Non-steroidal synthetics include Diethylstilbestrol and Dienestrol.

Physiological Actions of Estrogens

Estrogens promote the synthesis of clotting factors II, VII, IX, X, fibrinogen, and anti-thrombin.
Continuous estrogen exposure may lead to endometrial hyperplasia.
Estrogens lower LDL and raise HDL cholesterol levels.
They sensitize myometrium to oxytocin, aiding labor.
Estrogens decrease bone resorption, impacting bone health.

Indications for Estrogen Use

Treatment for hypogonadism in girls.
Administered for hormonal replacement therapy.
Used in contraception.
Recommended for osteoporosis management.
Useful in treating prostate carcinoma.
Address conditions like Turner's syndrome (gonadal dysgenesis).

Adverse Effects of Estrogens

Potential for gallstones and pulmonary embolism.
Increased risks for endometrial and breast cancer associated with long-term use.
Use of DES during pregnancy may increase vaginal adenocarcinoma risk in daughters.

Selective Estrogen Receptor Modulators (SERMs)

Clomiphene: Enhances FSH/LH secretion by inhibiting estrogen feedback on hypothalamus/pituitary; used to induce ovulation; risks of multiple pregnancies.
Tamoxifen: Acts as a partial agonist in certain tissues; used in advanced breast cancer, with endometrial cancer risk due to partial agonism.
Raloxifene: Agonist for bone and lipid metabolism; antagonist for endometrium and breast; prevents post-menopausal osteoporosis without endometrial cancer risk.

Aromatase Inhibitors

Anastrozole: Inhibits aromatase, reducing estrogen synthesis; indicated for post-menopausal breast cancer resistant to tamoxifen.

Progestins

Synthetic analogs of progesterone are categorized by generation based on structure and potency.
First generation: Norethindrone, Ethynodiol diacetate.
Second generation: Levonorgestrel, Norgestrel.
Third generation: Desogestrel, Norgestimate.
Fourth generation: Drospirenone.

Clinical Uses of Progestins

Administered for hormonal replacement therapy and contraception.

Adverse Effects of Progestins

Possible effects include breakthrough bleeding, hirsutism, and acne (androgenic side effects).
Alterations in lipid and glucose metabolism may occur.

Antiprogestins

Mifepristone: Acts as a progesterone receptor antagonist and glucocorticoid receptor antagonist; effective in post-coital pregnancy prevention and early pregnancy termination.

Hormonal Contraceptives

Two main types:
- Combination of estrogen and progestin: Inhibits gonadotropin release, especially LH surge during midcycle.
- Progestin-only options are also available.

Description

This quiz covers the essential aspects of gonadal hormones, focusing on estrogen types, including natural and synthetic variations. It also explores physiological actions and implications of estrogen exposure. Test your knowledge on this critical subject in endocrinology.