Week 3 - Female Endocrinology Flashcards
What is estradiol converted from?
From Testosterone, or bidirectionally from Estrone (E1)
What are 6 conditions associated with female hormone dysregulation?
PCOS Endometriosis Female infertility (of various aetiologies) Fibroids Adenomyosis Fibrocystic breasts
What is estriol made from?
Estrone (E1) or Estradiol (E2)
GnRH is released from _____
hypothalamus
GnRH stimulates the release of _______ from the anterior pituitary
FSH & LH
GnRH: pulsatile secretion every _____?
60-90 minutes
GnRH: negative feedback from ______ via ______, estrogen and testosterone
ovaries, via inhibin
FSH released from __________ in response to GnRH
anterior pituitary
function of FSH?
initiates and maintains growth of follicle
LH released from anterior pituitary in response to ____
GnRH
function of LH?
directs maturation of final follicle and ovulation
Estradiol released from the ovary during the proliferative phase has what effect on the hypothalamus?
positive feedback
- b/c estrogen causes the lining of the uterus to grow.
- estrogens initiate the formation of a new layer of endometrium in the uterus, histologically identified as the proliferative endometrium. The estrogen also stimulates crypts in the cervix to produce fertile cervical mucus, which may be noticed by women practicing fertility awareness
Inhibin released from the ovary during the proliferative phase has what effect on the anterior pituitary?
negative feedback
Estradiol released from the ovary during the secretory phase has what effect on the hypothalamus?
negative feedback
inhibin released from the ovary during the secretory phase has what effect on the hypothalamus?
negative feedback
During the secretory phase, the corpus luteum produces which hormone?
Progesterone.
The secretory phase is the final phase of the uterine cycle and it corresponds to the luteal phase of the ovarian cycle. During the secretory phase, the corpus luteum produces progesterone, which plays a vital role in making the endometrium receptive to implantation of the blastocyst and supportive of the early pregnancy, by increasing blood flow and uterine secretions and reducing the contractility of the smooth muscle in the uterus; it also has the side effect of raising the woman’s basal body temperature.
What is the difference between the ovarian and uterine cycles?
The menstrual cycle can be described by the ovarian or uterine cycle. The ovarian cycle describes changes that occur in the follicles of the ovary whereas the uterine cycle describes changes in the endometrial lining of the uterus. Both cycles can be divided into three phases. The ovarian cycle consists of the follicular phase, ovulation, and the luteal phase whereas the uterine cycle consists of menstruation, proliferative phase, and secretory phase.
Ovarian cycle: - Follicular phase - Ovulation - Luteal phase Uterine cycle - Menstruation - Proliferative phase - Secretory phase
Prolactin is secreted by the _____
pituitary
function of prolactin?
stimulates milk production in mammary glands
levels increased during pregnancy
suppresses GnRH during lactation & inhibits FSH & LH
Where is progesterone produced?
PRO GESTation hormONE
produced in ovaries by corpus luteum, in adrenal glands & in placenta during pregnancy
role of progesterone in secretory/luteal phase of menstruation?
Maintains endometrial lining (prepares uterus for implantation)
Makes cervical mucus impenetrable to sperm
Decreases contractility of uterine smooth mm.
If pregnancy does not occur, progesterone levels will decrease, leading, in the human, to menstruation. Normal menstrual bleeding is progesterone-withdrawal bleeding. If ovulation does not occur and the corpus luteum does not develop, levels of progesterone may be low, leading to anovulatory dysfunctional uterine bleeding.
What is estrogen produced?
ovaries, peripheral tissue, adrenal glands
What is the predominant form of estrogen?
Estradiol (E2)
2 hydroxyl groups
What is the least abundant form of estrogen?
Estrone (E1)
Can act as storage form of estrogen
1 hydroxyl group
When is estriol primary made?
pregnancy - by the placenta
3 hydroxyl groups
___ can be converted to E1 and back and both can be converted to __ (urine metabolite)
E2 can be converted to E1 and back and both can be converted to E3 (urine metabolite)
Why can phytoestrogens and xenoestrogens bind to estrogen receptors?
Estrogen receptors are able to bind to compounds with similar but relatively diverse structures (hence phytoestrogens and xenoestrogens)
The _________ cells make estradiol when provided with _________.
The granulosa cells make estradiol when provided with androgens.
ER alpha is found primarily where?
uterus
kidneys
liver
heart
ER beta is found primarily where?
ovaries prostate lungs GI tract hemopoietic system CNS
Estrone preferentially binds to which receptor?
ERa
Estriol preferentially binds to which receptor?
ERb
Estradiol preferentially binds to which receptor?
equally strong to ERa & ERb
What are the effects of estrogen throughout the body at puberty?
- 20-fold increase in estrogen
- increases size of reproductive organs & external genitalia, breast development
- changes vaginal epithelium from cuboidal to stratified
- development of stromal & ductal breast tissue & deposition of fat
estrogenic effect on bone?
- maintains bone density, mass
- closing of epiphyseal plates
estrogenic effect on brain?
- maintains mood
- sudden lowering, or consistently low levels can lead to low mood
estrogenic effect on CV system
- improves arterial blood flow
- helps maintain healthy HDL/LDL levels
- generally cardioprotective
estrogenic effect on reproductive organs
- uterine cell proliferation & endometrial thickening
- thickening of vaginal epithelium
What is the relationship between estrogen & cancer risk
- induces cell proliferation in some types of tissue causing an increase risk of cancer (by increasing risk of genetic errors)
- increases risk of breast cancer and uterine cancer
What is another name for aromatase?
estrogen synthase
what does aromatase do
- aromatase is responsible for the aromatization of androgens into estrogens
- primary mechanism of estrogen production in the body