Exam 4 - PCOS Flashcards
What are the symptoms of PCOS?
hyperandrogenism, chronic anovulation, polycystic
ovaries, insulin resistance and sometimes obesity
What are the different criteria for PCOS?
1991 NIH -
all of the three: hyperandrogenism, chronic anovulation, and exclusion of known disorders
2003 Rotterdam -
2 of the 3: hyperandrogenism, chronic anovulation, and polycystic ovaries with at least 12 (now 20) follicles each
What is the prevalence of PCOS?
5-10% of women
Often presents with insulin resistance/associated with obesity
What diseases is PCOS a risk factor for?
Type 2 Diabetes, Gestational diabetes, and cardiovascular disease
How does PCOS relate to hyperandrogenism?
GnRH pulse determines which gonadotropin is preferentially synthesized. In PCOS, there is a rapid GnRH pulse that favors LH over FSH resulting in a LH:FSH ratio greater than 1.
Increased LH and decreased FSH means the theca cells produce more androgens and there is less FSH to convert the androgens to estrogen in the granulosa cells via aromatization.
Hyperandrogenism results.
What are the symptoms that result from ovarian hyperandrogenism?
Hirsutism (dark, coarse, thick hair on the face, chest, abdomen, and back)
Acne (stimulated by androgens)
Adrogenic alopecia (male pattern hair loss)
How does hyperandrogenism affect female athletes with PCOS?
Female athletes with PCOS may have increased testosterone compared to females without PCOS, but it is nowhere near that of males. So, they may have increased athletic ability but not comparable to males.
How does PCOS relate to anovulation?
Women with PCOS have a large number of small follicular cysts that have arrested during follicular development before ovulation This is a result of androgen excess or genetic factors. Elevated androgens decreases the quality of the developing oocyte int he follicle, and low FSH is not sufficient to stimulate further follicle development.
Progesterone remains low because the corpus luteum never forms.
How does PCOS relate to infertility?
If follicle development is not completed and oocytes never ovulate, this can result in infertility.
How does PCOS affect AMH levels?
AMH is high (over 6) because the follicles arrest in the preantral/small antral phase when they are producing AMH but never end up ovulating (never stop producing AMH)
How does PCOS relate to insulin resistance?
PCOS patients are insulin resistant, which results in hyperglycemia. However, elevated blood glucose stimulates more insulin secretion, resulting in hyperinsulinemia.
How does PCOS relate to glucose infusion rate?
To maintain a hyperinsulinemic-euglycemic clamp, patients with PCOS had a much slower GIR. Patients who were overweight also needed a slower GIR, and patients who were both overweight and had PCOS had the slowest GIR.
Why is glucose uptake lower in PCOS patients?
increase pS of IR/IRS 1/2, decreases PI3K and GLUT4 translocation
What are the consequences of PCOS associated hyperinsulinemia regarding obesity?
When blood insulin levels remain elevated, liver SHBG output is inhibited which increases the circulating free androgens. Free fatty acids are also released from the liver, which increases adipose tissue growth to store excess glucose. Obesity is the result.
What are the effects of insulin on the theca cells?
Insulin further increases the activity of the theca cells. They become hypersensitive to insulin. 17a-hydroxylase activity is increased with insulin stimulation because of serine phosphoylation of P450c17 enzyme. This demonstrates selective insulin resistance because while most tissues become insulin resistant with PCOS, theca cells remain responsive and even become hypersensitive to insulin.
