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PHAR230 > M4: Gonadosteroids > Flashcards

M4: Gonadosteroids Flashcards

1
Q

Gonadal Hormones

A

FEMALE Sex Hormones:
1. Estrogens: develop and female sexual characteristics

  1. Progestins: control of ovarian cycle and maintain pregnancy

MALE Sex Hormones:
1. Androgens = develop and male sexual chracterisitics

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2
Q

Types of Estrogens

A
  1. Natural (Endogenous):
    Drug:estradiol = secreted by ovaries
  2. Semisynthetic
    Drug: thinylestradiol → inactive prodrug
    - Estradiol valerate
  3. Synthetic
    Drug: Mestranol and Stilboestrol
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3
Q

*Pharmacokinetics of Estrogens

A

Absorption Through:
- GIT
- Skin
- Mucous membranes (e.g., vaginal pessaries)

Transport by Binding to:
- Albumin
- Sex steroid-binding globulin

Half-life: 13 hours

Metabolism and Degradation:
- In the liver
- Synthetic estrogens are less prone to degradation than natural

  • Excretion through kidneys in urine
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4
Q

Therapeutic Indications of Estrogens

A

Contraception in females

Replacement therapy (estrogen deficiency):
- Menopausal symptoms (hormone replacement therapy; HRT)
- Female hypogonadism

Menstrual Disorders: e.g., menorrhagia

Acne

Prostatic cancer – anti-androgen effect

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5
Q

Female HYPOgonadism

A

Due to impaired ovarian function

Types:
- Pre-pubertal → delayed puberty
- Post-pubertal → secondary amenorrhea and infertility

Treatment of Primary Hypogonadism:
- Begins at 11-13 years of age
- Stimulate development of secondary sex characters and menstruation
- Stimulate optimal growth

Small doses of estrogen on days 1 to 21 of each month (mimic normal cycle)

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6
Q

HYPERestrogenemia

A

Increased estrogens levels

In males →
- Feminization e.g., gynaecomastia, soft voice, …
- Infertility

In females →
- Endometrial carcinoma (progestins reduce the risk)
- Breast cancer (effect of progestins unknown)

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7
Q

Antiestrogens

A
  1. Tamoxifen:
    - Potent estrogen receptor blocker in breast tissue
  • Used in the treatment of hormonally responsive breast cancer:
    Treatment following unilateral excision of breast cancer reduces risk of cancer in the second breast
  1. Clomiphene:
    - Selective estrogen receptor modulator (SERM):
  • Inhibits estrogen-mediated negative feedback on hypothalamus → Ovulation Induction: used in the treatment of infertility due to ovulation disturbances
  1. Letrozole:
    Aromatase enzyme Inhibitor → decrease estrogen synthesis

Indications:
- Hormonally responsive breast cancer
Only in post-menopausal women
- Ovulation induction – treatment of infertility (less chance of twins)
- Gynecomastia in men

Androgens

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8
Q

PROGESTINS:
- Types
- Therapeutic Indications

A

TYPES OF PROGESTINS
1. Natural (endogenous):
Drug = Progesterone: secreted by corpus luteum and placenta

  1. Synthetic:
    1st generation compounds:
    Drugs: Medroxyprogesterone, norethindrone, norgestrel

2nd generation compounds:
Drug: Levonorgestrel

3rd generation compounds:
Drugs: Desogestrel, gestodene, norgestimate
- Least androgenic effect

THERAPEUTIC INDICATIONS:
- Contraception in females
- Hormone replacement therapy (HRT)
Endometriosis (functional endometrial tissue outside the uterus)
- Endometrial carcinoma
- Dysmenorrhea (painful menstruation)
- Menstrual disorders

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9
Q

ANTIprogestins

A

Mifepristone (RU-486):

Mechanism: progesterone receptor blocker

Indication:
- Therapeutic abortion: alone = 70%
- Combined with prostaglandins → PGE 1 or 2: 95%

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10
Q

3 Hormonal Contraception Drugs

A
  1. Oral Contraceptives (OCC)
  2. Injections and implants
  3. Transdermal patch
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11
Q

*ORAL CONTRACEPTIVES (OCC)

A
  1. Combined OCC: combination of estrogen and progestin
    Most popular
    Types:
    - Monophasic: fixed dose
    - Bi- or triphasic: variable dose
  2. Progestin Minipill = low dose progestin

Examples of OCC:
1. Monophasic
- estrogen = ethinyl estradiol
- progestin = desogestrel

  1. Triphasic
    - estrogen = ethinyl estradiol
    - progestin = desogestrel

Combined OCC are taken daily for 21 days and stopped for 7 days
‡ Minipill is taken daily without a break

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12
Q

Oral Contraceptives (OCC)

  • Mechanism of Action
  • Adverse Effects of Combined OCC
  • Contraindication of Combined OCC
A

MECHANISM OF ACTION:
Estrogen-Progestin Combinations:
- Suppress ovulation: decrease GnRH from hypothalamus → decreases FSH & LH from pituitary
- Thicken cervical secretions (not optimal for sperm migration)
- Inhibit implantation

Low-Dose Progestin:
- Thicken cervical secretions (not optimal for sperm migration)
- Inhibit implantation
- Variable suppression of ovulation by effect on FSH/LH

ADVERSE EFFECTS OF COMBINED OCC:
1. Salt and water retention → edema → hypertension

  1. Vascular Disorders:
    - Thromboebolic – coronary / cerebrovascular disease
    - Higher risk in smoker women above 35 years
  2. Headache – migraine
  3. Depression
  4. Postpill amenorrhea

CONTRAINDICATIONS OF COMBINED OCC:
1. Absolute:
- Pregnancy
- Breast feeding
- Thromboebolic disease: coronary artery disease + cerebrovasular disease
-Breast/cervical/endometrial cancer
- Undiagnosed vaginal bleeding

  1. Relative:
    - Hypertension
    - Impaired liver function
    - Migraine
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13
Q

Contraceptive Injections and Implants

A

Long acting progestins

Injections:
- IM injection every 3 months
- Drug = Medroxyprogesterone (provera)

Implants:
- SC insertion of small capsules
- Effective for 3 – 5 years
- Drug = Levonorgestrel (norplant)

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14
Q

Hormone Replacement Therapy

A

Estrogen replacement in postmenopausal woman
- Low dose compared to contraceptives

Progestin can be added to reduce the risk of endometrial carcinoma

Benefits:
- Prevention of changes associated with menopause:
- Osteoporosis (decrease in bone mass)
- Flushing, headaches and insomnia
- Genital tract atrophy
- Cardiovascular disease (improvement of lipid profile)

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15
Q

Types of ANDROGENS

A
  1. Natural (Endogenous):
    - Testosterone
    - Dihydrotestosterone (DHT)
    - Dehydroepiandrosterone (DHEA)
    - Androstenedione
  2. Synthetic:
    - Methyltestosterone
    - Ethyloestrenol
    - Stanozolol
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16
Q

ANDROGENS:
- Actions
- Therapeutic Indications

A

MECHANISM OF ACTION OF ANDROGENS:
- Regulate gene expression by activating a nuclear receptor

EFFECTS:
- Development of primary & secondary male sex characters
- Maturation of sperms

ANABOLIC EFFECT:
- Some synthetic androgens have more anabolic than androgenic activity (e.g., stanozolol)

THERAPEUTIC INDICATIONS:
1. Hormone replacement:
- Male hypogonadism
- Hypopituitarism

  1. Anemia refractory to treatment:
    - Androgens stimulate erythropoiesis
  2. Breast cancer (estrogen- or progestin-receptor positive):
    - Androgens downgrade receptor expression
  3. Anabolic Agents:
    - Compensate for protein loss: e.g., after surgery or immobilization
    - Often abused by body builders and athletes …
17
Q

Male Hypogonadism

A

Types:
- Primary: testicular failure
- Secondary: hypothalamic-pituitary disease

Treatment: androgen replacement
- Stimulate development of male secondary sex characters
- Maintain muscle and bone mass

Regimen:
- Oral: TDS
- Transdermal patch: every 24 hours
- IM injection: every 2-3 weeks
- Subdermal implants: every 4-6 months

18
Q

Hyperandrogenemia

A

In females:
- Virilization symptoms: hirsutism, acne, amenorrhea, clitoral enlargement and deepening of voice

  • During pregnancy: masculinization of external genitalia of infants

In prepubertal male children:
- Precocious puberty

19
Q

4 Anti-Androgens

A
  1. Androgen suppressors
  2. Androgen receptor inhibitors
  3. Estrogens
  4. Progestins
20
Q

Androgen Surpressors

A

Drug = Leuprolide Acetate

Mechanism:
GnRH analog – interrupts GnRH receptors →
Decrease FSH & LH (in males or females) →
Decrease testosterone or estrogen to ±10% of basal levels

Used to Treat:
- Prostatic carcinoma
- Endometriosis
- Breast cancer

Administration: IM or SC injection every 1, 3, 4 or 6 months

21
Q

Androgen Receptor Inhibitors

A

Drug = Cyproterone Acetate

Mechanism:
- Androgen receptor competitive antagonist
- Progestin action

Used to Treat:
- Prostatic carcinoma
- Precocious puberty in boys
- Acne
- Hirsutism and virilization in women

Adverse effects:
- Hepatotoxic

Administration: oral

22
Q

Male Oral Contraceptive

A

Drug = Gossypol:
Derived from seeds of cotton plant

Action:
- Inhibition of sperm production
- Efficacy is comparable to the female OCC

Adverse effects:
- Irreversibility
- Hypokalemia

PHAR230 (16 decks)

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