Reproductive Hormones Random Flashcards

Reproductive Hypothalamus & Hormones

• GnRH (Gonadotropin-releasing hormone):
  • Stimulates the Pituitary Gland.

Pituitary Gland Products

• FSH (Follicle Stimulating Hormone):
  • Stimulates follicular maturation and maturation of the egg.
• LH (Luteinizing Hormone):
  • Stimulates follicular maturation and maturation of the egg.
  • Induces oocyte release.
  • When the follicle is released, the corpus luteum makes progesterone.

Estrogen

• Defines females and is the primary sex hormone.
• Responsible for sex characteristics and reproduction.
• Forms:
  • Estradiol
  • Estrone
  • Estriol
• Effects:
  • Increases HDL (High-density lipoprotein).
  • Decreases LDL (Low-density lipoprotein).
  • Cardioprotective: Important because women are less prone to heart attacks than men.
  • Increases bone deposition, reducing the risk of osteoporosis (especially important post-menopause when estrogen levels drop).
  • Beneficial for the brain, kidney, skin, and vasculature.

Progestins

• Promote breast development.
• Work with estrogen to increase endometrial lining thickness.
• Increase vasculature of the endometrium.
• The endometrial lining is shed during menstruation.

High Estrogen Levels

• Induce negative feedback.
  • Progestins inhibit GnRH, FSH, and LH, preventing egg production. This is the mechanism by which hormonal birth control works.

Hormone Contraception

• All hormone contraception methods are Pregnancy Category X.
• Estrogens and progestins are used to prevent pregnancy.
• Administration:
  • Typically started on day 5 of the menstrual cycle and continued through day 21.
• Issues:
  • Forgetting to take pills is a concern.
    • If one pill is missed, take two the next day. Contraception is generally still effective.
    • If two pills are missed, take two pills for the next two days and use additional forms of contraception.
• Adverse Effects of Hormonal Contraceptives:
  • Cancer: Potential association with HPV.
  • Glucose Elevation: Can increase glucose levels; patients with diabetes should monitor closely.
  • Hypertension: Risk increases with age, dose, and length of use. Regular BP monitoring is important.
  • Migraines: Estrogen may either decrease or increase the incidence of migraines.
  • Common Side Effects: Nausea, edema, and breast tenderness related to high estrogen levels.
  • Thromboembolic Disorders: Estrogens promote blood clot formation.
• Mechanism of Action:
  • High levels of progestin and estrogens prevent ovulation through negative feedback, suppressing LH and FSH release.
  • Make the endometrium less receptive to implantation.
  • Used to promote timely and regular periods.

Types of Hormonal Contraceptives

• Monophasic:
  • Less than 1% failure rate.
  • Constant dose of estrogen and progestin.
• Bi-Phasic:
  • Less than 1% failure rate.
  • Constant estrogen dose with two different levels of progestin.
• Tri-Phasic:
  • Less than 1% failure rate.
  • Estrogen and progestin levels change in three distinct phases throughout the pill pack.
• Quad-Phasic:
  • Less than 1% failure rate.
  • Estrogen and progestin levels change in four distinct phases throughout the pill pack.
• Mini Pill:
  • Progestin-only.
  • 1-4% failure rate.
• Cessation:
  • It can take several months up to a year to restore fertility after cessation.

Other Contraceptive Choices

• Medroxyprogesterone (Depo Provera):
  • Intramuscular injection lasting for 3 months.
• Subdermal Implant:
  • Effective for 3 years.
• Transdermal Patch:
  • Applied 3 times per cycle, each patch lasting 7 days.
• Vaginal Ring (NuvaRing):
  • Releases estrogen and progestin.
  • Used for 3 weeks, then removed for one week.
• Intrauterine Device (IUD):
  • Placed up around the cervix.

Emergency Contraception

• Levonorgestrel (Plan B):
  • Prevents implantation.
  • Dosing:
    • Two 0.75mg doses taken 12 hours apart, OR
    • One 1.5mg dose
  • Mechanism of Action:
    • Decreases endometrial receptivity.
    • Decreases implantation.
  • Administer as soon as possible after unprotected intercourse.
  • Efficacy: If used properly, the likelihood of pregnancy is 1-2%. Unprotected intercourse has an 8% risk of pregnancy.
• Mifepristone with Misoprostol (RU486):
  • Chemical abortion.
  • Can be used within the first 63 days of pregnancy.
  • Mifepristone:
    • Causes the placenta to separate from the endometrium.
    • Softens the cervix.
    • Causes some uterine contractions.
    • If used alone within 3 days of unprotected intercourse, it inhibits progesterone receptors and is 100% effective in preventing pregnancy.
  • Misoprostol:
    • Causes major uterine contractions to expel the fetus.

HRT - Hormone Replacement Therapy

• Used post-menopausally.
• Consists of a combination of estrogen and progestins OR estrogen alone.
• Used to delay post-menopausal symptoms.
• Risks:
  • Increases risk of MI (myocardial infarction), stroke, dementia, thrombus formation (blood clots), and breast cancer.
• Estrogen alone has lower risks than combination therapy.
• Provides protection against hip fractures.

Uterine Dysfunction

• Amenorrhea:
  • Absence of menstruation (no menses).
  • Can be caused by low body fat.
• Endometriosis:
  • Endometrial tissue located outside the uterus.
  • Responsive to hormones, causing pain and cramping.
• Oligomenorrhea:
  • Infrequent menses.
• Menorrhagia:
  • Excessive or prolonged menses.
• Breakthrough Bleeding:
  • Bleeding between periods.
• Medroxyprogesterone (Depo Provera):
  • Pregnancy Category X.
  • Synthetic progestin.
  • Inhibits the effects of estrogen on the uterus.
  • Reestablishes normal hormonal balance.
  • Uses: Contraception, endometriosis, breakthrough bleeding, amenorrhea.

Breastfeeding

• Oxytocics:
  • Increase uterine contractions.
• Tocolytics:
  • Decrease uterine contractions.
• Oxytocin:
  • Released from the posterior pituitary.
  • Increased levels lead to increased uterine contractions.
  • Important for parturition (childbirth).
  • Contracts muscles in breasts, stimulating milk glands to increase milk letdown or ejection.
  • Nipple stimulation increases oxytocin release.
  • Synthetic oxytocin is called Pitocin.
• Prolactin:
  • Tonically inhibited by D2 receptors.
  • Synthesis increases 10-20 fold during pregnancy due to high estrogen and progesterone levels.
  • Increases milk production and prepares the breast for milk production.
  • Stimulated by GnRH and thyroid releasing hormone.
  • Inhibited by D2 receptors.

Tocolytics

• Decrease uterine contractions and suppress premature labor.
• Magnesium Sulfate:
  • Previously used, now considered OLD
• Nifedipine (Procardia):
  • L-type calcium channel blocker.
  • Used to prevent contractions.

Female Infertility

• Not on exam.
• Causes: Pelvic infection, physical obstructions, lack of ovulation, hypothalamus issues, pituitary or ovary problems.

Female Sexual Desire Drug

• Addyi (flibanserin):
  • Patient must sign a waiver.
  • Dispensed from a certified pharmacy.
  • Prescribed by a certified and authorized doctor.

Male Reproductive System

• Hypothalamus:
  • Releases GnRH (Gonadotropin-releasing hormone).
• Anterior Pituitary:
  • LH increases testosterone production.
  • FSH increases sperm production.
• Testosterone provides feedback and inhibits GnRH in the pituitary.
• Testosterone Abuse:
  • High testosterone from external sources, such as in powerlifters, stops the production of LH and FSH.
  • Can cause men to become sterile.
• High GnRH - Chemical Castration:
  • Stops the system, leading to testicular atrophy.

Testosterone

• Increases muscle mass and strength.
• Increases erythropoietin leading to an increase in red blood cells and hemoglobin.
• Promotes the development of secondary sexual characteristics: deep voice and body hair.
• Can increase aggression, which tends to decrease with age.

Primary Hypogonadism

• Testicular failure due to mumps, trauma, inflammation, high fever, or autoimmune disorders.

Secondary Hypogonadism

• Hypothalamus issue leading to decreased GnRH and decreased LH and FSH.
• Causes: Cushing's syndrome, thyroid disorders, or estrogen-secreting tumors.

Sexual Dysfunction in Males

• Benign Prostatic Hypertrophy (BPH):
  • Testosterone is converted to dihydrotestosterone (DHT) by 5-alpha reductase.
  • DHT stimulates prostate growth.
• Finasteride (Proscar):
  • Used for BPH to decrease DHT formation.
  • Mechanism of Action: 5-alpha reductase inhibitor.
• Smooth Muscle Relaxation:
  • Alpha-1 receptors stimulate contractions of the bladder neck and urethra.
• Alpha-1 Antagonists:
  • Tamsulosin (Flomax):
    • Relaxes the smooth muscle, increasing voiding (stream strength) and promoting complete voiding.

Erectile Dysfunction

• Related to decreased nitric oxide formation.
• Sildenafil (Viagra):
  • Takes 30 minutes to work and lasts 4-6 hours (12 hours for 100mg dose).
  • Side effects: Nasal congestion, headache, visual changes (blue tint).
  • Contraindications: Do not use with hypertension medications; allow 4 hours between doses.
  • Originally developed as a hypertension medication.
• Tadalafil (Cialis):
  • Do not use with hypertension medications; allow 4 hours between doses.