Endocrine 6 (Reproduction) Flashcards

1
Q

What hormone regulates the menstrual cycle?

A

GnRH regulates the secretion of FSH and LH

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2
Q

Endogenous Estrogens
- Examples

A

Estrone, Estradiol, Estriol

Estradiol = Most Potent

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3
Q

Synthetic Estrogens
- Examples

A

Ethinylestradiol, Mestranol

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4
Q

Estrogen
- Receptor Signalling

A

Reproductive Action
- Nuclear Estrogen Receptors (ER)
–> ER alpha and ER beta
–> Transcription Factors that regulate gene expression

Vascular Action
- GPCR
–> GPR30 or GPER
1. Activation of endothelial nitric oxide synthase (eNOS)
2. Increases NO
3. Vasodilation

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5
Q

Combined Pill
- Contains?

A

Ethinylestradiol (Synthetic Estrogen)
- Natural Estrogen are susceptible to hepatic metabolism

2nd Generation Progestogens
- Norethisterone, Levonorgestrel, Ethynodiol
or
3rd Generation Progestogens
- Desogestrel, Gestodene

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6
Q

Combined Pill
- MOA

A

Estrogen increases Negative Feedback on anterior pituitary
- Suppresses Ovarian Follicular Development

Progestogen increases Negative Feedback on anterior pituitary
- Inhibit LH secretion –> Prevents Ovulation

Both work in combination to make reproductive tract unsuitable for contraception and implantation

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7
Q

Combined Pill
- Acne: Estrogen vs Progesterone

A

Acne is caused by free androgens

Estrogen: Increases sex hormone binding globulin that remove free androgens
–> Decrease Acne

Progesterone: Increases amount of androgen
–> Increases Acne

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8
Q

Combined Pill
- Adverse Effect

A

Thromboembolism
- Patients that smoke or have a history of hypertension should avoid 3rd generation Progestogens

Increase Blood Pressure in some Women
- Caused by increase in circulating angiotensinogen
- Stop using combine pill and switch to a progestogen only therapy

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9
Q

Combined Pill
- Beneficial Effect

A

Reduced risk in ovarian and endometrial cancer

Decreased menstrual symptoms

Reduced iron deficiency anemia

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10
Q

Hormonal Contraceptives
- Breast Cancer

A

Actually do not increase the risk of breast cancer
- Only appears like it does due to greater monitoring when using contraceptives
- Allows us to catch the cancer early

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11
Q

2nd Generation Progestogen vs
3rd Generation Progestogen

A

3rd gens are less likely to cause acne
Higher risk for thromboembolism

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12
Q

Progestogen Only Pill
- Contains?

A

Norethindrone (1st Generation)
or
Ethynodiol (2nd Generation)

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13
Q

Progestogen Only Pill
- MOA

A
  • Makes cervical mucus inhospitable to sperm
  • Inhibits implantation (Altering endometrium)
  • Alters motility and secretions of fallopian tubes

Alternative for people who experience blood pressure increase from estrogen

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14
Q

Postcortical Contraception

A

Oral Dose of Levonorgestrel
- Used in emergency, dose is repeated 12 hours later
- Causes nausea and vomit
–> Take with Dimenhydrinate (Gravol)

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15
Q

Long-Acting Progestogen-Only Contraception

A

Depot Medroxyprogesterone
- Given intramuscularly (Slow release of progestogen)
- Menstrual irregularities are common
- Infertility may persist for months even after stopping treatment

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16
Q

Non-Biodegradable Capsule Contraception

A

Subcutaneous Insertion of Levonorgestrel
- Slowly releases progestogen for 5 years

17
Q

Oxytocin
- Regulation

A

Released facilitated by:
- Cervical dilation
- Estrogen causes greater expression of receptor

18
Q

Oxytocin
- MOA

A

Usually given by IV
1. Binds to GPCR (Gq)
2. PLC breaks PIP2 into IP3 and DAG
3. IP3 causes an increase in intracellular calcium
4. Calcium activates Calmodulin
5. Calmodulin stimulates MLCK
6. MLCK induce uterine contraction

Also causes a release of prostaglandins that cause uterine contraction

19
Q

Oxytocin
- Adverse Effects

A
  • Hypotension (When administered rapidly)
  • High dose can cause sustained contraction
    –> Reduces blood flow and O2 delivery
    –> Fetal distress and potentially death

Have to do slow increments up to maximum dose

20
Q

What causes uterine contractions

A

Oxytocin
- Estrogen increase expression of receptor
Cervical dilation
Prostaglandins

21
Q

Ergometrine
- MOA

A

May act on Alpha-Adrenoceptor and partly on 5-HT Receptors
- Stimulates Uterine Contraction

Stronger effect on relaxed uterus
Minimal effect on contracted uterus

Alpha-Adrenoceptor
- Stimulates Uterine Contraction
Beta Adrenoceptor
- Inhibits Uterine Contraction

22
Q

Ergometrine
- Adverse Effects

A

Vomiting (Effects D2 receptors in the chemoreceptor trigger zone)
- Use D2 antagonist to treat vomiting
–> Domperidone
–> Metoclopramide
–> Profenamine

23
Q

Mifepristone
- MOA

A

Competitive Antagonist / Partial Agonist of Progesterone
- Sensitizes uterine muscle to progesterone
- Allows for a lower dose of prostaglandin

Followed by a prostaglandin to induce myometrial contraction and expel the fetus
- Misoprostol (Prostaglandin E1 Analogue)
- Gemeprost (Prostaglandin E1 Analogue)

24
Q

Atosiban
- MOA

A

Competitive antagonist of oxytocin receptor
- Delays labour

Prevents increase of IP3
- No increase in intracellular calcium
- No increase in MLCK for uterine contraction

Suppresses oxytocin-induced release of prostaglandins

25
Q

Clomiphene
- MOA

A

Estrogen Antagonist
- Treats Infertility

Inhibits negative feedback of estrogen on hypothalamus and anterior pituitary
- Promotes Gonadotrophin Release

Result: Promotes FSH secretion

26
Q

GnRH Agonists
- MOA

A

Continuous: Down regulates receptor
- Decreases secretion of FSH and LH
- Less follicle development and ovulation

Pulsatile: Assists in fertility

27
Q

GnRH Agonists
- Other Considerations

A

Given if Clomiphene treatment fails

Given in a pulsatile fashion for infertility treatment

Given in a continuous fashion to collect eggs
- Continuous dose suppresses pituitary gland –> Suppresses FSH and LH
- Give recombinant FSH and LH to induce ovulation
- Allows for the collection of egg for in vitro fertilization

28
Q

Phosphodiesterase V Inhibitors
- MOA

A

Inhibits PDE V
- Prevents inactivation of cyclic GMP

  1. Sexual Stimulation
  2. Nitrergic Nerves release NO into smooth muscle cells of penis
  3. NO activates GC
  4. GC converts GTP into cGMP
  5. cGMP is an allosteric activator for PKG
  6. Causes vasodilation

Result: Penis fills with blood

29
Q

Phosphodiesterase V Inhibitors
- Adverse Effects

A

Hypotension (Was originally used to treat hypertension through vasodilation)
- Do not take if patient is on nitrates, may slow heart too much

Visual Disturbances (Inhibition of PDE VI)
- Avoid use if patient has hereditary degenerative retina