|
Who ?
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Estrogen Names
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Production Sites
(by aromatase enzyme)
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Aromatase produced
in response to:
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Comments
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Reproductive
Age Women
|
ESTRADIOL
(E2)
(17-beta
ESTRADIOL)
(circulating hormone)
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Ovaries
(granulosa cells)
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FSH
|
▪
ESTRADIOL
functions as a circulating hormone
(acting on distant target tissues) - Most abundant and potent natural
form of
estrogen in
non-pregnant females
during reproductive years.
▪ANDROSTENEDIONE
from
ovarian theca cells or
adrenal cortex is principal substrate for production of
ESTRADIOL
in ovarian granulosa cells.
|
|
Men
and
Women
|
ESTRONE
(E1)
/ESTRADIOL
(E2)
(Localized metabolism)
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Adipose tissue
(mesenchymal cells)
Bone
(chondrocytes, osteoblasts)
Skin Fibroblasts
|
Gluco-corticoids;
Class 1 Cytokines
|
▪ESTRONE (E1)
is less
abundant than E2
and E3 -
but the only one of the 3 present in any
quantity in and post-menopausal women ;
▪Adipose and
Skin cell aromatization is the major source for
circulating ESTRADIOL
in
men and post-menopausal women
-adrenal
ANDROSTENEDIONE(a derivative of PROGESTERONE )is converted by aromatase to
ESTRONE
(E1), which is converted to ESTRADIOL
by 17βhydroxysteroid dehydrogenase (17β-HSD) activity.
▪
ESTRONE is a
reservoir for
ESTRADIOL -
ESTRONE
is converted to
a long-lived storage derivative, calledESTRONEsulfate,
which can be converted as needed to the more active
ESTRADIOL.
ESTRONE
is
weaker than
ESTRADIOL.
▪
Adipose tissue is the greatest peripheral
source of
aromatase in both males and
females
contributing to
ESTRADIOL
production.
▪ESTRONE
acts
locally at production sites -
Circulating
estrogensare
escapees from local metabolism from such as adipose tissue, brain and
bone; Thus low circulating
estrogen
levels
in
postmenopausal women
and
men have
little bearing on concentrations in
estrogen-producing
tissues. E.g. the
estrogen
responsible for a breast tumor (has up to 10x circulation levels), brain
(cognitive) functions, or bone mineralization is that produced locally
at those sites.
|
|
Men
|
ESTRADIOL (E2)
ESTRONE (E1)
(Circulating hormone)
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Testes
(Leydig cells, Sertoli cells)
|
FSH
|
▪
Responsible for at most 15-20% of total
circulating
ESTRADIOL;
▪Lehdig cells convert
TESTOSTERONE
(produced by
testes' Sertoli cells)
➔
ESTRADIOL
to direct spermagenesis
http://erc.endocrinology-journals.org/cgi/reprint/6/2/131.pdf
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