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What is PCOS characterized by?
- elevated androgen levels
- menstrual irregularity
- insulin resistance
What is the underlying problem in PCOS?
FSh never rises to a level sufficient to stimulate follicular development beyond the pre-ovualtory phase so there are several follicles that are present with none achieving dominance and there is also a persistent secretion of estradiol at low levels insufficient to trigger the switch to posit feedback to that tis a promotion of the LH surge
What is the menstrual cycle for a person with PCOS?
There basically is no cycle. Levels of FSH remain constant and the levels of progesterone are absent. The follicles are arrested in persistent early 4-8 mm phase
What are the 2 metabolic syndromes that accompany PCOS?
- Insulin resistance: we may have normal serum glucose but in response to a glucose load women with PCOS have an increased insulin response.
- GnRH and Lh pulsatility: LH pulsatility is increased in both frequency and amplitude and GnRh may be abnormal as well. Why? well who knows maybe because insulin can trigger pituitary secretion or maybe because there is some genetics?
- Hyperandrogenism: So the insulin and the LH can act on the theca cells and this can cause them to hypertrophy (hyperthosis) and produce more testosterone and because there is suppression of the sex hormone binding globulin testosterone circulates unbound making it more biblical active and these increased levels also suppress follicular development which causes infrequent ovulation dn irregular bleeding
So what are the differences between being a thin woman with PCOS and a fat woman?
So in obese women, the increase of androgen secreted by the ovary is aromatized to weak androgens such as estrone and the increased serum levels of these weaker estrogens provide further - feedback on the pituitary to decrease FSH production creating a visous cycle leading to more androgen pxn. many women stop having regular menstrual cycles an this is thought to be due to the hypothalamic disregualtion
So why do many PCOS patients not have menstrual flow every month?
So progesterone is what stabilizes enometrial growth and regression of the corpus luteum.. The decline in the progesterone levels is what triggers menstruation but without the formation of the corpus luteum there is no progesterone pxn and so the endometrium is arrested in the proliferative phase with no shedding that leads to long periods of time w/o bleeding but when it does happen it is due to unstable irregularly developed endometrium that sheds at random and bleeding may be heavy, prolonged and unpredictable.
What are the treatments for PCOS?
- weight loss/excersise
- combined oral contraceptives
- ovulation induction agents (clomiphene)
- insulin sensitizers (metformin)
- Anti-androgens (spirinolactone)
Why are oral contraceptives good for PCOS?
- estrogen in the pill provides the - feedback in the pituitary to suppress gonadotrophin secretion and a decrease in LH will help to slow down the secretion of androgen.
- exogenous estrogen also induces the liver to secrete more sex hormones binding globulin so that the androgens that are present in the serum will be bound and not biologically active
- Monthly cycling of the hormone also causes the orderly monthly shedding of the endometrium thereby creating regular periods and preventing hyperplasia and cancer
What is the effect of clomiphene on PCOS women>
So clomophone is an ovulation induction agent. it is an estrogen analog that has an antagonistic effect int he pituitary's trogen recpets so by blocking the - feedback loop of estrogen on the hypothalamus and pituitary it allows for an increased secretion of FSH required to stimulate an ovarian follicle to becoming an ovulatory follicle
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