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.