Block 5: Gonads Breese Flashcards
1
Q
What is the function of Gonadotropin Releasing Hormone (GnRH)?
A
Stimulates anterior pituitary gland to release FSH and LH
2
Q
What is the function of FSH and LH?
A
- Increases the secretion of estrogen and progesterone in females
- Increases the secretion of testosterone in males
3
Q
What occurs in the phases of ovulation?
A
Follicular: LH and FSH concentrations increase due to GnRH
Ovulation: Follicle released from ovary -> secretes estrogen
Luteal: Progesterone prepares the endometrium to receive and nourish a fertilized egg
4
Q
What is the MOA of GnRH antagonists?
A
- Competitively and reversibly bind to GnRH receptors in the pituitary gland, blocking the release of luteinizing hormone (LH) and follicle-stimulating hormone (FSH) from the anterior pituitary
- Abolish gonadal sex hormone production and suppress sex hormone levels
5
Q
What are the types of GnRH antagonists?
A
- Cetrotelix (Cetrotide)
- Degarelix (Firmagon)
- Ganirelix
- Elagolix (Orilissa)
6
Q
Danazol
Brand, MOA, Indication
A
Danocrine
MOA: Inhibits release of GnRH and consequently, the gonadotrophins (FSH and LH), preventing the mid-cycle surge in the levels of FSH and LH during the menstrual cycle
Indication: Endometriosis
7
Q
Describe the biosynthesis of estrogens and testosterone?
A
8
Q
What is the primary female sex hormone?
A
Estrogen
9
Q
What is the function of estrogen?
A
- To develop secondary female sex characterisitcs
- Thickens endometrium
- Regulate menstrual cycle
10
Q
How is estrogen regulated?
A
FSH and the LH
Hypothalamus → GnRH → Pituitary → FSH → Follicle → Estrogens
11
Q
What are the estrogen receptors?
A
ERa and ERb
12
Q
What are the types of estrogen preparations?
A
Natural: estradiol
Synthetic: mestranol, ethinyl estradiol
13
Q
What are the clinical uses for estrogen?
A
- Oral contraception
- Hypogonadism
- Postmenopausal Hormonal Therapy
- Suppress ovulation in patients with intractable dysmenorrhea or hirsutism
- Fertility treatments
14
Q
What is the pregnancy rate of using contraception perfectly?
A
0.5–1 per 100 woman years
15
Q
What are the ADRs of estrogens?
A
- Tenderness of breasts
- NV
- Anorexia
- Retention of salt and water
- Breakthrough breeding
- Thromboembolism, carcinoma
16
Q
CI of Estrogens?
A
- Pregnancy
- Incomplete bone growth
- Genital bleeding
- Strke
- TEDX, HDX
- BRCA gene
17
Q
DDIs for estrogen?
A
↓ efficacy of oral anticoagulants and hypoglycemic agents
↑ adverse effects of tricyclic antidepressants
↑ the effects of oxytocin on the uterus.
St. John’s wort may cause loss of contraceptive or hormonal-replacement efficacy of estrogens
18
Q
What are SERMs?
A
Tissue specific activity
1. Estrogenic activity for bone growth;
2. Anti-estrogenic for uterine endometrial growth (raloxifene) and in estrogen receptor positive (ER+) breast cancers
19
Q
Raloxifene
Brand, MOA, INdication, ADR, Interactions
A
Evista
MOA: High affinity for both ER-a and ER-b
Indication: Osteoporosis
ADR: DVT and PE
Interaction: Decrease warfarin efficacy
20
Q
What are the types of SERMs?
A
- Toremifene (Fareston)
- Ospemifene (Osphena)
- Raloxifene (EVISTA)
21
Q
What are aromatase inhibitors?
A
- blocks the local production of estrogens in hormonally-responsive tissues
- Do not have the bone protecting activity of tamoxifen, and may require adjuvant therapies to prevent bone loss
22
Q
What are the types of aromatase inhibitors?
A
Steroidal: exemestane (AROMASIN)
Non-steroidal: anastrozole (ARIMIDEX), letrozole (FEMARA)
23
Q
Clomiphene
Brand, MOA
A
Clomid
MOA: Increases secretion of GnRH and gonadotrophins and induces ovulation
24
Q
What are the anti-estrogens?
A
Clomiphene (Clomid)
Fulvestrant (FASLODEX)
25
Where is progesterone produced?
1. Adrenal glands
2. Gonads
3. Brain
4. Placenta
26
How is progesterone regulated? What is the primary effect?
Stimulated by the production of LH
Hypothalamus → GnRH → Pituitary → LH → Corpus luteum → Progesterone
**Primary effect:** Prepares uterus for implantation by the proliferation of endometrium and prepares body for pregnancy
27
What is the action of natural progesterone?
Destroyed by digestive enzymes and acids when used orally
28
What is component is in all oral contraceptives?
Progesting, synthetic form of progesterone
29
Why is progestin in all oral contraceptives?
In adequate doses, they inhibit ovulation
30
Due to progesterone's low bioavailability, what products were created to increase efficacy?
1. Medroxyprogesterone (Provera, Depo-Provera): 17-a-hydroxy-progesterone derivatives have substitutions at C17 that slow hepatic metabolism
2. Norethindrone: 19-nor testosterone derivatives display primarily progestational with moderate estrogenic and androgenic activity
3. Norgestrel / Levonorgestrel: Replacement of the 13-methyl group of norethindrone with a13-ethyl substituent
4. Desogestrel and Norgestimate
31
Clinical use for progestins?
**Contraception:**
1. Used with estrogen in combined oral contraceptive pill
2. As progestin-only contraceptive pill
3. As injectable or implantable progestin-only contraception
4. As part of an intrauterine contraceptive system
Combined with estrogen for estrogen replacement therapy for women with an intact uterus to prevent cancer
32
ADRs of progestins?
1. Acne
2. Fluid retention, weight change
3. Depression
4. Libido changes
5. Breast discomfort
1. Premenstrual symptoms
1. Irregular menstrual cycles
1. Thromboembolism
33
Mifepristone
| Brand, MOA, Indication
RU 486, Mifeprex
**MOA:** competitive antagonist of progesterone
**Indication:** Terminate pregnancies (abortifacient)
**Available under REMS program**
34
What is Korlym?
Mifepristone used to control hyperglycemia secondary to hypercortisolism in adults with CUshings
35
Clincial uses for contraception?
1. Withdrawal bleeding and dysmenorrhea
2. Menstrual blood loss in menorrhagia
3. Endometriosis
4. PMS
5. Acne
6. Perimenopause
36
What are the types of hormonal contraceptive products?
Combination hormonal – pill, patch, vaginal ring
Progestin-only-pill, long-acting/depot injections, implant, levonorgestrel IUD
37
38
What are the types of combination hormonal contraceptive products?
Combinations of estrogens and progestins:
**Monophasic:** Constant dosage of both components during the cycle.
**Biphasic or Triphasic:** Dosage of one or both components is changed once (biphasic) or twice (triphasic) during the cycle.
39
What is the MOA of estrogen and progestin?
1. Prevents ovulation by inhibiting LH/FSH release
2. Thins endometrium
3. Thickens cervical mucous
40
41
What are the estrogen contraception products?
Mestranol and ethinyl estradiol
1. Mestranol is biologically inactive and must be metabolized to ethinyl estradiol
2. Ethinyl estradiol is 2X more potent than mestranol
3. Alkyne decreases hepatic metabolism
42
What are the progestin contraception products?
**19 NOR steroids**
Estranes
Gonanes
Drospirenone: progestin and antiandrogen medication
Dienogest: progestogenic activity and antiandrogenic activity
43
What are estranes?
Androgenic activity and estrogenic / anti-estrogenic actions, rapidly absorbed (Norethindrone)
44
What are gonanes?
More potent than estranes:
* Norgestrel and levonorgestrel have higher androgenic activity
* Norgestimate, Desogestrel have lower androgenic activity
45
What is monophasic contraception? Products?
The concentrations of estrogens and progestins are fixed in the pill, which is taken for 21 days followed by 7 days of “hormone-free” pills
1. Mestranol (50 µg) + norethindrone (1.0 mg)
2. Ethinyl estradiol (20-50 µg) + a progestin (estranes or gonanes, 0.15-1.5 mg).
46
What are biphasic contraception? Products?
Limit exposure to the higher concentration of the progestin early in the cycle
Ethinyl estradiol (fixed concentration) + norethindrone (lower concentration in the first 7-10 days and then higher concentration for the next 11-14 days) or other progestin (desogestrel, levonorgestrel)
47
What is quadriphasic contraception?
Four concentrations during the month
Natazia (estradiol + dienogest)
48
Extended Regimen Contraception
| Products, Brands, Dosing, Advantages
**Products:** Levonorgestrel / ethinyl estradiol and either placebo or ethinyl estradiol tablets 0.01 mg tablets)
**Brand:** Quasense, Seasonale, Seasonique, LoSeasonique
**Dosing:** 91-day courses of tablets: 84 full doses, followed by 7 days of placebo or low dose estradiol (Seasonique)
**Advantages:** Period once every 3 months
49
What is seasonique?
Incorporates low dose estrogen rather than placebo, limits blating, hormonal fluctuations, and breakthrough bleeding
50
What are the disadvantages of contraceptive patches?
1. Two-fold increase in risk of non-fatal VTE
2. Application site reactions
3. Not as effective in women weighing >198 pounds
4. Higher rates of breast pain and dysmenorrhea
5. Difficult to conceal
51
What are cotnraceptive patch products?
Onsura, Xulane: Norelgestromin anda ethinyl estradiol
52
What is a contraceptive ring?
Flexible circular device that goes inside the vagina slowly releasing hormones through the vaginal wall into the bloodstream to prevent pregnancy
53
What are contraceptive ring products?
NuvaRing and Eluryng: contains etonogestrel and ethinyl estradiol
Annovera: segesterone acetate / ethinyl estradiol
**Monthly birth control**
54
What are the absolute contraindications of combo contraceptives?
Smokers over 35 (may use progestin only)
55
What are the health risks of combo contraceptives?
Loer-dose OC formulations (<50mcg estrogen) are safe
1. Breast cancer risks
2. Cervical neoplasia
3. VTE (DVT, PE): risk factors like smoking and underlying dx increase risk
4. Arterial
* Stroke
* MI: Increased risk in over 35 who smoke
5. Oral estrogen in TG levels
6. Failure leading to pregnancy
56
What are examples of progestin only products?
**PO:** norethindrone (Camila)
**Subdermal implants:** Etonogestrel (Nexplanon)
**IM:** Medroxyprogesterone (Depo-Provera)
**IUD**
57
Nexplanon
| MOA
Single rod implant with etonogestel and a membrane made of ethylene vivyl acetate
3 years
58
How qualify for progestin only contraceptives?
Post-partum
Breastfeeding
CV risk factors
59
Common ADRs of progestin only contraceptives?
Irregular bleeding and spotting
60
What are the advantages of emergency contraception?
Reduces the chance of pregnancy by 75% if taken within 72hrs of unprotected sex
61
What are indications for postcoital contraceptives?
**Morning after pill/Plan B:** The first dose should be taken within 72 hours after unprotected intercourse and the 2nd dose 12 hours later
Intended to prevent pregnancy after unprotected intercourse
62
Plan B products?
Ella (ulipristal acetate)
63
How does emergency contraception prevent pregnancy?
1. Inhibits/delays ovulation
2. Hormones may alter sperm or ovum transport
3. Hormones may alter endometrium making it inhospitable to implant an embryo
64
When is hormone replacement therapy used?
HRT restores estrogen decrease from menopause
Low estrogen may lead to vasomotor symptoms, osteoporosis, and urogenital atrophy
Must use progestin in woman with intact uterus to prevent endometrial hyperplasia
65
What are the benefits of short-term HRT?
1. Improvement of postmenopausal sx
2. Prevention and tx of osteoporosis
66
ADRs of HRT?
Routine use can increase risks of uterine and breast cancer
67
What are the HRT formulations?
**Medroxyprogesterone (MPA):** adding progestins can limit endometrial hyperplasia
**Conjugated estrogen:** Permarin (tablets, cream, injectable)
**Combo:**
* PREMPRO (PREMARIN plus MPA) given at fixed dose daily
* PREMPHASE 14/14 (PREMARIN for 28 days and MPA during days 14-28)
**Vaginal cream:** Premarin
**Ring:** Estring, estradiol vaginal ring
68
Describe the biosynthsis of testosterone?
69
What is the main natural occuring androgen?
Testosterone: has both androgenic and anabolic effects
70
What are the intermediates of testosterone?
Androstenedione (17b HSD) -> Testosterone (5a-reductase) -> DHT
71
What is the phsiological and medical function of testosterone?
**Physiological:** FSH and LH stimulation
**Medical:** Treatment of hypogonadism
72
What is andropause?
Progressive decline in total and free testosterone levels
73
What is the treatment for andropause?
Testosterone
*ADR: ↑ LDL, BPH, and urinary sx
STRM and SARM or Selective Testosterone (or Androgen) Receptor Modulators are drugs in development
74
What are examples of androgen formulations?
**17a Hydroxyl Group Esters** are more lipophilic and converted to testosterone in the circulation:
1. Testosterone propionate
2. Testosterone enanthate
3. Testosterone undecanoate
**17a Alkylated Testosterone** have reduced hepatic metabolism, reduced androgenicity, directly toxic to hepatocytes
1. Methyltestosterone (Metandren)
75
What are ADRs of androgen tx?
1. Feedback inhibition
2. Anabolic Steroid and Androgen Abuse is 100-200 X the normal daily production in men
76
What are examples of androgen antagonists? Indication?
Spironolactone is competative inhibitor of aldosterone and copetes with DHT reducing 17a-hydroxylase activity lowering testosterone and androstenedione
Treatment of hirsutism in women
77
5a-reductase inhibitor examples?
**Finasteride (Proscar):** BPH and male patterned baldness (Propecia)
**Dutasteride (Avodart):** BPH
