PCOS Flashcards
PCOS
polycystic ovarian syndrome
endocrine organs involved
hypothalamus, pituitary gland, ovary, adrenal glands
endocrine system
They release various hormones to
regulate various processes
throughout the body
- Small changes in hormone levels
can have drastic effects on the
body/function
Gonadotropin
Releasing Hormone
(GnRH) released from…
hypothalamus
The hypothalamus releases GnRH in “pulses” and the
frequency of these pulses control the hormone that is released
GnRH
regulates the release of LH and FSH from the anterior
pituitary.
Low frequency pulses release FSH, and high frequency pulses release LH
Follicle Stimulating
Hormone
(FSH) released from…
anterior pituitary
FSH function
FSH signals oocytes to grow and mature into secondary follicles
during ovulation. FSH receptors are located around follicular cells.
These receptors control the release of estrogen at appropriate times
during the ovulation cycle.
estrogen released from
granulosa cells of developing follicle
estrogen function
Estrogen initially inhibits release of LH until the oocytes have
matured into secondary follicles. Once this occurs, Estrogen uses a
positive feedback loop to stimulate the anterior pituitary to release
LH.
Luteinizing Hormone
(LH) released from…
anterior pituitary
LH function
Induces ovulation and helps prepare body for fertilized egg to
implant in uterine lining. Stimulates Theca cells to produce
androgens. Increases activity of proteolytic enzymes that degrade
ovarian wall, stimulating oocyte release into fallopian tubes.
Progesterone released from
theca and luteinized granulosa cells
progesterone function
Prepares uterus for implantation of a fertilized egg and pregnancy
Androgens released from
theca cells
Androgen function
Androgens are converted to estrogen.
*Important androgen for this presentation: testosterone
ovulation 1
Hypothalamus releases Gonadotropin
releasing hormone (GnRH), in slow
“pulses”, which travels to the anterior
pituitary
ovulation 2
The GnRH stimulates the anterior
pituitary to release follicle stimulating
hormone (FSH).
Small amounts of LH are released
ovulation 3
FSH travels to the ovary
and stimulates a few primordial
(immature) follicles to develop.
ovulation 4
Granulosa cells of developing follicle release estrogen.
extra androgens conversion
Small amounts of LH circulating in the blood stimulates theca cells to release androgens into granulosa cells. The androgens are converted into estrogen and released.
ovulation 5
Estrogen provides feedback to the
hypothalamus. It initially inhibits LH
release, however once it reaches the
critical estrogen level, it stimulates the release of LH via rapid pulsing of
GnRH.
ovulation 6
LH travels to the ovary and increases
activity of proteolytic enzymes that
weaken the ovarian wall, releasing the oocyte.
T/F granulosa cells remain in ovary after oocyte released
true
ovulation 7
Remaining theca and
granulosa cells form corpus
luteum and release
progesterone and small
amounts of estrogen.
ovulation 8
If a fertilized egg does not implant, estrogen and progesterone levels drop cause the corpus luteum to degrade. Also causes the superficial and middle layers of the endometrium lining of the uterus to be broken down and
released.
3 hallmarks of PCOS
irregular periods
hyperandrogenism
polycystic ovaries
Genetic causes
5-alpha-reductase gene
estrogen receptors
5-alpha-reductase gene
responsible for converting testosterone into dihydrotestosterone
(DHT), a more potent androgen
elevated activity in PCOS patients
estrogen receptors
altered alpha and beta subunits impact follicular
development
environmental
endocrine disruptors
advanced glycation end products
endocrine disruptors
Substances that mimic steroid hormones and interact with endocrine
system impairing normal binding, metabolism, and cellular function,
and by causing oxidative stress
endocrine disruptor ex
Plastics can contain a variety of toxic chemicals
such as Bisphenol-A (BPA), phthalates, and
Perfluoroalkyl substances, such as PFOS and
PFOAs. These chemicals, along with microplastics
can enter food and function as endocrine
disruptors in the body
Advanced Glycation End Products (AGEs)
-protein or lipid that reacts with a sugar
-Women with PCOS have high levels of AGE
>can trigger insulin resistance and deposition of AGEs in ovarian tissue
»causes anovulation and
»hyperandrogenism
polycystic ovary
- follicle doesn’t mature and no ovulation occurs
- non-ovulated follicles turn into cysts in the ovary
- corpus luteum isn’t created; no surge in progesterone
low progesterone feedbacks to
hypothalamus to increase rapid pulsing to increase GnRH
release of LH and ↓release of FSH leads to
production of androgens in theca cells
insulin resistance can occur, which causes increase production in pancreas…. leads to
increased production of androgens in theca cells
insulin sensitivity/ resistance can lead to increased…
hypothalamus hormone production that acts as positive feedback loop
