Repro Endocrinology Flashcards by Caroline Motschwiller

What are some requirements for a normal progression to puberty?

adequate sleep (GnRH first secreted at night, GH secreted at night)
adequate body fat
consistent source of estrogen (need to have properly functioning end organ = ovaries)

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Define precocious puberty

Premature sexual development

-defined as

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What is gonadotropin-dependent precocious puberty?

Central or true precocious puberty

early maturation of the H-P-gonadal axis
so GnRH initiated early, the cycle is normal but just turned on too early

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What is gonadotropin-independent precocious puberty?

Not real puberty b/c no FSH/LH or GnRH involved

caused be excess secretion of sex hormones (estrogens or androgens) from either the gonads or the adrenal glands
this hormone secretion if independent of both GnRH or gonadotrophs

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Is precocious puberty more common in boys or girls?

5 x more common in girls

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What is the most common cause of precocious puberty? What are some other causes?

More common is idiopathic (we never find out why)

estrogen, androgen, or HCG producing neoplasm
CNS lesion
McCune-Albright syndrome

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What is McCune-Albright syndrome?

Mutation in a receptor on granulosa cells that renders them constantly activated to make estrogen

=> excess estrogen => precocious puberty and bone abnormalities
-also associated w/ cafe-au-lait skin pigmentation

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Define delayed puberty

Absence of incomplete development of secondary sex characteristics > 12 in girls, > 14 in boys (in the US)

-problem can be anywhere in the system: hypothalamic, pituitary, thyroid, chromosomal, autoimmune

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Genotype of Turner’s syndrome

50% 45, XO
other 50% 46,XX or 46,XY

-need to X chromosomes for ovaries to develop properly, so even tho the H-P part of the axis is acting normally, there’s no ovaries => no estrogen produced

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What are the two phases of the menstrual cycle when referring to the

(a) ovary
(b) uterus

Menstrual cycle split into 2 phases

(a) Ovary: Follicular phase (follicles develop) –> Luteal phase (after ovulation the corpus luteum remains and makes hormones)
(b) Uterus: Proliferative (endometrium growing) –> Secretory

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Adrenarche

Activation of the adrenal medulla

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Gonadarche

Activation of the gonads (ovaries/testes)

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Pubarche

Appearance of pubic hair

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Thelarche

Appearance of breast tissue (in females)

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Menarche

Onset of first bleed, aka your first period

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Can one use Tanner staging of pubic hair to assess ovarian function? Why?

Pubic hair is dependent on adrenarche, or activation of the adrenal gland, NOT the activation of the HPA axis => pubic/axillary hair doesn’t tell you anything about ovarian function

What is the typical age of adrenarche?

Around 6 yoa
-When the adrenal glands start producing androgens

-This is NOT the activation of the HPA axis (so don’t confuse the two!)

Name some factors that can determine the onset of puberty

Genetics (common ages in families, may be associated w/ KISS1R), physiologic and psychologic stress, body fat (overweight => period may come early, underweight => period may come late), geographic region, country’s development status

What gene is the gatekeeper of puberty?

KISS 1R = Kisspeptin receptor

thought to be key to turning on GnRH secretion
indicated in the genetic link btwn age of menarche

What is considered a normal length for a menstrual cycle?

Normal ranges from 25-35 days w/ 28 days being the average

What is considered a normal duration for menstruation?

Normal cycle lasts for 3-7 days, average is 5 days

How long are the two phases of the menstrual cycle?

On average, follicular/proliferative is 14 days. The luteal/secretory phase is more stringent and is always 14 days

=> in a 30 day cycle, ovulation occurs on day 16

-it can vary how long it takes for a follicle to develop, but it is more exact on how long the corpus luteum will survive and make progesterone/estrogen

How can blood work help you distinguish if a woman is in the proliferative or secretory phase of the menstrual cycle?

Estrogen is present in both phases, but progesterone is ONLY present in the secretory phase once the corpus luteum is around to secrete it

=> if progesterone is detectable (> 2) the woman is in the secretory/luteal phase

How can you tell if a woman has ovulated?

If progesterone is present

Which cells in the ovary are under the influence of LH?

Theca cells- catalyze the first reaction of estradiol synthesis

Which cells in the ovary are under the influence of FSH?

Granulosa cells- takes androstenedione and testosterone (made in the theca cell) and aromatizes them to estrone (inactive) and estradiol (active) respectively

What is inhibin?

Member of the TGF-beta family that inhibits FSH

What is activan?

Member of the TGF-beta family that activates FSH

What can be measured as an indirect marker of ovarian reserve?

AMH = anti-Mullerian hormone = MIF (released in males to cause degeneration of the paramesonephric ducts) - AMH is expressed in the granulosa cells of the recruited primordial follicles => higher the AMH = the higher the primordial cell reserve - higher ovarian reserve = more fertile

Why is tracking body temperature not that helpful for women trying to conceive?

B/c the progesterone that is released from the corpus luteum which makes the temperature rise is only present AFTER ovulation occurs => by the time you see the rise in the body temp it's about 2 days after ovulation has already occurred

What is the most reliable predictor of when ovulation will occur?

The estrogen peak!!! The estrogen peak is what causes the LH surge, then ovulation occurs 10-12 hours after the LH surge

What happens to the granulosa cells after ovulation?

They become luteinized into the corpus luteum and start secreting progesterone

What happens to the cervical mucous throughout the cycle?

Rise in estrogen increases the production and causes thinning of the cervical mucus => makes it easy for the sperm to penetrate the cervix

What is spinnbarkeit?

The ability of the cervical mucus to stretch (um ew)

What is a corpus alibcans?

The scar that the corpus luteum involutes into if fertilization/implantation does not occur => there is no HCG to maintain the corpus luteum

When does progesterone peak?

About one week after ovulation | -corpus luteum is at its largest, then starts degrading when it gets no signal from HCG to stay

What phase of the menstrual cycle is this 30 yo F in: - irregular cycles ranging from 35-60 days - estradiol 100 pg/ml, LH: 8 IU/ml, progesterone 8.4 ng/ml

Luteal -has to be luteal/proliferative b/c it's after ovulation since progesterone is so high (> 2)

On what day of the cycle will this 20 yo F ovulate? ``` -cycle length: 27 days Labs on day 4 show: -estradiol: 45 pg/ml LH: 3 IU/ml progesteron ```

27 - 14 = 13, day 13 The luteal phase is fixed at 14 days - it's the follicular phase which is variable - so ovulation is ALWAYS 14 days before the end of a cycle

On what day of her cycle is this 27 yo F on? - cycle length: 28 days - estradiol 260, LH 28, progesterone .2

Day 14! - already had her peak of estradiol (>300) that caused the LH surge - hasn't ovulated yet b/c no progesterone