Block 2 Lecture 1 -- Menstrual Cycle Flashcards
How long does menses last?
3-5 days (2-7 is normal)
When is normal onset of menses?
12 yo
What is the other name for aromatase?
CYP19
What causes the LH surge?
estradiol ≥ 200 pg/mL x 48 hours
When does the LH surge occur relative to ovulation?
10-16 hours prior
What is the best predictor of ovulation?
LH surge
When is [progesterone] greater than [estrogen]?
ONLY during luteal phase of menstrual cycle
What is the time period over which the CL degenerates?
9-11 days if no fertilization
When is hCG detectable?
6-8 days post-fertilization
When does the luteal-placental shift occur?
12 weeks post-fertilization
What hormones are produced by the placenta?
progesterone and estriol
When is hCG produced?
immediately following blastocyst implantation in the endometrium
Describe the structures of FSH and LH.
- 36kDa heteromeric glycoproteins
- secreted by AP
- common alpha, unique beta subunits
What is the half-life of FSH?
3-4 h
What is the half-life of LH?
20 minutes
What is the E# designation for estrone?
E1
What is the E# designation for estradiol?
E2
What is the E# designation for estriol?
E3
What is E1
estrone
What is E2
estradiol
What is E3
estriol
When is E1 most abundant?
estrone most abundant…
– post menopause
Where is E1 primarily produced
estrone produced …
– primarily from fat
When is E2 most abundant?
estradiol most abundant…
– in repro women
When is E3 most abundant?
estriol most abundant…
– during pregnancy (and only detectable during pregnancy)
Where is E2 produced?
ovaries
Where is E3 produced?
in placenta from E2 or E1, or from circulating DHEA
What is the most abundant steroid in circulation?
DHEA
What are the non-menstrual effects of estrogens?
1) secondary sex characteristics
2) increased bone formation
3) improved lipids
4) opposition of aldosterone
5) positive mood
6) neuroprotection
7) softer skin
8) increased liver protein synthesis
What is the concentration of progesterone in the follicular phase?
less than 2 ng/mL
What is the concentration of progesterone in the luteal phase?
5+ ng/mL (normally 10-15)
What is the concentration of progesterone in pregnancy?
100-200 ng/mL
What are the progestogens?
1) progesterone
2) 17-alpha-hydroxyprogesterone
Where is progesterone formed?
corpus luteum
adrenals
Where is 17-alpha-hydroxyprogesterone formed?
adrenals
What is the principle circulating progestogen?
progesterone
What is the concnetration of progesterone in the luteal phase?
10-15 ng/mL
What is the concentration of 17-alpha-hydroxyprogesterone in the luteal phase? 3rd trimester?
1-5 mg/mL
30 ng/mL
When is 17-alpha-hydroxyprogesterone concentration elevated?
pregnancy
CAH
Describe the structure of inhibin
peptide dimer
What is the function of hCG?
maintain CL
maintain progesterone production
What are the functions of progesterone?
1) suppress uterine contractility, maternal immune response to fetus, inhibit lactation, promote preparation of lactation
2) sperm attractant via activating Ca channels
3) prepares endometrium for implant
4) forms thick cervical mucous to inhibit sperm movement
5) used by embryo to make glucocorticoids and sex steroids
Where are the targets of progesterone?
1) uterus
2) breast
3) CNS – neuromodulator, neuroprotector
What is the function of FSH?
- stimulate granulosa cells to produce estrogen by upregulating aromatase
- stimulate inhibin production
- in males: spermatogenesis
How long is menses?
21-40 days; (u=28)
Which phase of the cycle is most likely to vary in length?
follicular, esp. after menarche and before menopause
What is non-pharm tx for dysmenorrhea?
- topical heat up to 12h
- exercise
- low-fat diet
When is the usual onset of PMS?
1-2 weeks prior to menses
What is non-pharm tx for PMS?
1) decrease caffeine, EtOH, sugar, salt
2) increase exercise
3) vitamin b6 (50-100 mg/day) + Calcium
What is the incidence of PMS?
75%, most common between 25-35 yo
What are the symptoms of dysmenorrhea?
– crampy pelvic pain 1-3 days before menses
+/- menorrhagia
+/- nausea/vomiting
+/- headache
What percentage of women experience recurrent dysmenorrhea?
25%
What are the causes of secondary dysmenorrhea? Most common?
most common = endometriosis
others: uterine polyps, pelvic infections, cervical stenosis
What percentage of PMS patients develop PMDD?
3-8%
What is the primary target of estrogens?
ER-alpha
– primarily ovary, uterus, breast
