Estrogens and Androgens

Vocabulary flashcards summarizing key hormones, drugs, mechanisms, uses, adverse effects, and pharmacology from the Estrogens and Androgens lecture.

Sex hormones

Estrogens and androgens produced by the gonads, essential for conception, development, and puberty.

Estradiol

Most potent natural estrogen, principal estrogen in premenopausal women.

Estrone

Metabolite of estradiol; primary circulating estrogen after menopause.

Estriol

Weak estrogen produced in significant amounts during pregnancy by the placenta.

Synthetic estrogens

Orally effective estrogens (e.g., ethinyl estradiol) with reduced first-pass metabolism.

Aromatization

Final step in estrogen synthesis converting androgens to estrogens.

Estrogen mechanism of action

Diffuses into cells, binds nuclear receptors, alters gene transcription to produce proteins.

Hormone therapy (HT)

Use of low-potency estrogens ± progestogen to relieve menopausal symptoms.

Conjugated equine estrogens

Oral sulfate esters of estrone/equilin obtained from mare urine for menopausal therapy.

Progestogen add-on in HT

Progestin combined with estrogen in women with uterus to lower endometrial cancer risk.

Micronized estradiol

Particle-size-reduced estradiol with improved oral bioavailability.

Transdermal estradiol

Patch/gel delivering estradiol while avoiding first-pass metabolism.

Selective Estrogen Receptor Modulators (SERMs)

Agents with tissue-selective estrogen agonist/antagonist activity.

Tamoxifen

SERM used for treatment/prevention of estrogen-responsive breast cancer.

Raloxifene

SERM that antagonizes breast/uterus but benefits bone; prevents osteoporosis.

Bazedoxifene

SERM combined with estrogens to treat menopausal symptoms without endometrial stimulation.

Clomiphene

Partial estrogen agonist that induces ovulation by increasing gonadotropins.

Ospemifene

SERM indicated for dyspareunia associated with menopause.

SERMs adverse effects

Hot flashes, nausea, thromboembolism (raloxifene), endometrial cancer risk (tamoxifen).

SERMs pharmacokinetics

Orally absorbed; tamoxifen metabolized by CYP3A4/2D6; enterohepatic recycling.

Progesterone

Natural progestogen from corpus luteum, placenta, testes, and adrenals.

Luteal phase progesterone action

Maintains secretory endometrium and inhibits gonadotropins, preventing ovulation.

Progestin

Synthetic progestogen with improved oral stability (e.g., norethindrone).

Medroxyprogesterone acetate

Progestin used orally, IM, or SC; injectable form gives 3-month contraception.

Progestins androgenic activity

19-nortestosterone derivatives can cause acne/hirsutism; drospirenone is less androgenic.

Mifepristone

Progesterone receptor antagonist used with misoprostol for medical abortion.

Combination oral contraceptive

Estrogen (ethinyl estradiol) plus progestin pill preventing ovulation.

Monophasic pill

Fixed estrogen/progestin dose for 21 days followed by placebo interval.

Triphasic pill

Constant estrogen with escalating progestin doses to mimic cycle.

Extended-cycle pill

84 active pills + 7 placebo, reducing withdrawal bleeds.

Contraceptive transdermal patch

Weekly ethinyl estradiol + norelgestromin patch; less effective >90 kg.

Contraceptive vaginal ring

Monthly device releasing ethinyl estradiol + etonogestrel.

Progestin-only pill

Daily low-dose norethindrone mini-pill; safe in breastfeeding, less effective.

Injectable contraceptive

IM/SC medroxyprogesterone acetate every 3 months; may cause weight gain, bone loss.

Etonogestrel implant

Subdermal rod providing 3-year contraception; a long-acting reversible contraceptive.

Levonorgestrel IUD

Intrauterine device releasing progestin for 3–5 years; treats heavy bleeding.

Copper IUD

Non-hormonal device effective up to 10 years.

Emergency contraception – levonorgestrel

Single 1.5 mg dose within 72 h post-coitus; pregnancy risk 0.2–3 %.

Ulipristal

Progesterone agonist/antagonist for emergency contraception within 5 days.

Contraceptive hormone MOA

Estrogen lowers FSH; progestin blocks LH & thickens cervical mucus.

Contraceptive adverse effects – estrogen

Breast fullness, nausea, fluid retention, hypertension, thromboembolism.

Contraceptive adverse effects – progestin

Depression, libido changes, acne, hirsutism.

Contraceptive contraindications

Thromboembolic disease, estrogen-dependent tumors, liver disease, pregnancy.

CYP3A4 inducers & OCs

Drugs like rifampin reduce contraceptive efficacy; backup barrier needed.

Testosterone

Principal human androgen produced by Leydig cells; converted to DHT or estradiol.

5α-Dihydrotestosterone (DHT)

Potent metabolite of testosterone formed by 5α-reductase, active in skin/prostate.

Androgen functions

Male maturation, spermatogenesis, muscle protein synthesis, hemoglobin rise, bone preservation.

Testosterone mechanism

Binds nuclear receptor; feedback inhibits hypothalamic–pituitary gonadotropins.

Testosterone formulations

Transdermal, topical, buccal, implant, or IM esters; oral inactive due to first pass.

17α-alkylated androgens

Orally active testosterone derivatives (e.g., methyltestosterone) with hepatic toxicity risk.

Oxandrolone

17α-alkylated DHT analogue with strong anabolic activity.

Anabolic steroid misuse

Illicit use to increase muscle mass; causes growth stunting, infertility, mood disorders.

Androgen adverse effects – males

Priapism, decreased sperm, gynecomastia, prostate growth.

Androgen adverse effects – females

Virilization, acne, voice deepening, menstrual irregularity.

Androgen adverse effects – general

↑LDL, ↓HDL, edema, hepatic damage (17α-alkylated), MI/stroke risk.

Danazol

Weak androgen with antiestrogenic activity for endometriosis & fibrocystic breast disease.

Antiandrogens

Agents blocking synthesis or receptor binding of androgens; treat prostate cancer.

5α-Reductase inhibitors

Finasteride & dutasteride; lower DHT to treat BPH and androgenic alopecia.