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Sex Differentiation
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▪ Promotes formation of female secondary sex characteristics:
growth of a girl's sex organs, breasts and pubic hair.
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▪ Effeminization when
estrogen to
TESTOSTERONE ratio
increases. E.g. Breast growth, higher voice, loss of body hair, decrease
in muscle mass, increase in fatty tissue, prostate enlargement, change
in sex drive;
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Protein Synthesis
|
▪ Estrogen
action: The role of specific RNA and protein synthesis;
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Reproductive Functions
|
▪ Decreases libido (sex drive);
▪ Helps regulate menstrual cycle;
▪ Stimulates endometrial growth;
▪ increases uterine growth;
▪ ESTRIOL
produced by placenta is involved with maintaining pregnancy
and initiating labor.
▪ Breast-feeding stimulates
estrogen production -
which stimulates production of the PROLACTIN hormone to increase milk
production.
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▪ ESTRADIOL
modulates sex drive, erectile function and spermotogenesis in
men - for libido,
estrogen is to men what
TESTOSTERONE is to women.
Estrogen receptors and
aromatase (enzyme that converts
testosterone to
estrogen) are abundant in brain,
penis, and testes, organs important for sexual function. In the brain,
estradiol synthesis is increased
in areas related to sexual arousal.
PubMed
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Reproductive organ cancers
|
▪
Promotes hormone-sensitive reproductive organ cancers -
treatment of endometrial and breast cancer involves suppression of
estrogen production;
ESTRADIOL
promotes an oncogene, Bcl-2 (expressed
at high levels, oncogenes help turn a normal cell into a tumor cell).
▪
ESTRADIOL increases expression of genes that are responsible
for directing production of both androgen
and estrogen hormone receptors.
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Regulates Fluid balance
|
▪Regulates salt / water retention;
▪ Increases growth hormone;
▪ Increases
CORTISOL, SHBG (Sex-Hormone
Binding Globulin) -binds ESTRADIOL
(and TESTOSTERONE) in
blood and thus inhibits their bioavailability, since only "free"hormones
are active)
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Structural
|
▪ Accelerates height growth;
▪ Reduces muscle mass;
▪ Maintains blood vessels /skin;
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Shortened height
|
▪ Can cause
early epiphseal closure near the end of puberty - thus limiting
height
|
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Protects against heart disease / Blood Clotting
|
▪ Increases HDL & triglycerides
/ Decrease LDL & fat deposition in coronary arteries;
▪ Blood Coagulation - Increase
circulating level of
factors
2,
7,
9,
10,
antithrombin III, plasminogen / Increase
platelet adhesiveness
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GI Tract
|
▪ Reduces bowel motility;
▪ Increases cholesterol in bile;
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Lungs
|
▪ Promotes lung function by supporting
avioli
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Preserves bone density
|
▪ Helps decrease bone
loss slightly - by slowing bone resorption (osteoclast
activity); antagonizes the effects of PTH, minimizing the loss of calcium
from bones,
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Decreases fat burning
|
▪ Increases subcutaneous
fat deposits/decreases fat-burning by stimulating SNS.
As an Alpha 2 adrenergic agonist, estrogen
increases/activates Alpha2 adrenoceptors (A2As), which
inhibit fat burning (A2As react to neurotransmitters EPINEPHRINE,
NOREPINEPHRINE, and isoprenaline, for a sympathetic effect; NOREPINEPHRINE
is one of the body's primary fat burning agents), but
when estrogen binds to the A2A
(taking NOREPINEPHRINE's "seat"), it creates a negative
feedback loop inhibiting the release of fat-burning NOREPINEPHRINE.
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Melanin
|
▪ Increases
pheomelanin, reduces
eumelanin
|
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Anti-aging for Skin
|
▪ Prevents decrease in
skin collagen in post-menopausal women. Topical
and systemic estrogen therapy
increases skin collagen content / skin thickness/ skin moisture (increases
acid mucopolysaccharides and hyaluronic acid, and possibly maintains
stratum corneum barrier function); Possible anti-wrinkle effect on elastic
fibers;
See: ESTRIOL-The
WEAK, Protective Estrogen
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