Action of Estradiol

In women, estradiol is a steroid hormone produced primarily by the ovaries and adrenal glands. Estradiol has a direct affect on the function of the reproductive system, the nervous system, the cardiovascular system and the skeletal system.

Blood sugar levels, skin and other tissues and functions are also significantly influenced by estradiol. Like all steroid hormones, excessive amounts of estradiol can contribute to a number of increased health risks. Though proper estradiol levels are critical for the prevention of osteoporosis, the actions of this hormone extend far beyond bone health.
Therefore it is crucial that proper levels also be maintained in all women.
Following is a list of some of the actions and functions of estradiol. More information and more references can be found in the book Discover Your Menopause Type?

Estradiol & The Endometrium
Excessive estradiol, or estradiol that is not opposed by progesterone or another progestogen, can increase the risk for developing endometrial cancer 1, 2.

Estradiol & The Vagina
Estradiol deficiency can result in increased vaginal dryness and atrophy. This can be relieved with estradiol (or other estrogen) replacement, resulting in less vaginal pain, itching and burning as well as less painful intercourse 3.

Estradiol & The Urinary Tract
A deficiency of estradiol is associated with increased urinary tract infections, which are diminished with estrogen replacement 4. Estradiol deficiency may cause or contribute to urinary incontinence, which is decreased with estrogen replacement 5, 6, 7, 8.

Estradiol & The Libido
Estradiol can directly increase sexual desire, interest and responsiveness 9, 10, 11, 12, 13. It also plays a role in increasing vaginal lubrication and satisfaction during sex. 14

Estradiol & Blood Sugar and Insulin Levels
Estradiol improves blood sugar (blood glucose) metabolism and decreases risk of developing hyperinsulinemia 15, 16, 17, 18. It increases the uptake of glucose by muscle cells 19, 20.

Estradiol & The Brain, Mood and Memory
Estradiol can significantly improve or alleviate depression in postmenopause women 21, 22. Estradiol is needed for normal the function of neurotransmitters that affect mood and memory 23, 24, 25.

Estradiol & The Breasts
Estradiol helps maintain the size and density of breast tissue, though excess amounts increase risk of some forms of breast cancer, or cause breast pain 26.

Estradiol & The Skin
Estradiol has a positive effect on skin thickness, skin collagen, water content, skin softness and blood flow to the skin 27, 28, 29.

Estradiol & The Bones and Osteoporosis
Estradiol decreases the development and the activity of bone clearing osteoclast cells 30, 31. It also increases the bone building ability of osteoblast cells directly 32, 33, 34.

Estradiol &The Heart
Estradiol lowers total cholesterol levels, and also lowers LDL (bad cholesterol) levels 35 while increasing HDL (good cholesterol) levels 36. Estradiol also causes a reduction in the level of Lipoprotein (a), which result sin a significantly reduced risk of developing heart disease 37, 38.

References:
(1) - Gray LA Sr, Christopherson WM, Hoover RN. Estrogens and endometrial carcinoma. Obstet Gynecol 1977 Apr;49(4):385-9
(2) - Smith DC, Prentice R, Thompson DJ, Herrmann WL. Association of exogenous estrogen and endometrial carcinoma. N Engl J Med 1975 Dec 4;293(23):1164-7
(3) - Coope J. Hormonal and non-hormonal interventions for menopausal symptoms. Maturitas 1996 Mar;23(2):159-168
(4) - Raz R, Stamm WE. A Controlled Trial of Intravaginal Estriol in Postmenopausal Women with Recurrent Urinary Tract Infections. N Engl J Med 329:753-6, 1993
(5) - Phillips JI, Davies I. A comparative morphometric analysis of the component tissues of the urethra in young and old female C57BL/ICRFAt mice. Invest Urol 1981 May;18(8):422-5
(6) - Bjornsdottir LT, Geirsson RT, Jonsson PV. Urinary incontinence and urinary tract infections in octogenarian women. Acta Obstet Gynecol Scand 1998 Jan;77(1):105-9
(7) - Lovatsis D, Drutz HP. The role of estrogen in female urinary incontinence and urogenital aging: a review. Ostomy Wound Manage 1998 Jun;44(6):48-53
(8) - Formosa M, Brincat MP, Cardozo LD, Studd JWW. Collagen; The Significance in Skin, Bone and Bladder. IN: Lobo RA. Treatment of the Postmenopausal Woman, Basic and Clinical Aspects. Lippincott-Raven Publishers. 1996
(9) - Myers LS. Methodological review and meta-analysis of sexuality and menopause research. Neurosci Biobehav Rev 1995;19(2):331-341
(10) - Beard MK, Curtis LR. Libido, menopause, and estrogen replacement therapy. Postgrad Med 1989 Jul;86(1):225-228
(11) - Cutler WB, Garcia CR, McCoy N. Perimenopausal sexuality. Arch Sex Behav 1987 Jun;16(3):225-234
(12) - Iatrakis G, Haronis N, Sakellaropoulos G, Kourkoubas A, Gallos M. Psychosomatic symptoms of postmenopausal women with or without hormonal treatment. Psychother Psychosom 1986;46(3):116-121
(13) - Dow MG, Hart DM, Forrest CA. Hormonal treatments of sexual unresponsiveness in postmenopausal women: a comparative study. Br J Obstet Gynaecol 1983 Apr;90(4):361-366
(14) - McCoy NL, Davidson JM. A longitudinal study of the effects of menopause on sexuality. Maturitas 1985 Sep;7(3):203-210
(15) - Cagnacci A, Tuveri F, Cirillo R, Setteneri AM, Melis GB, Volpe A. The effect of transdermal 17-beta-estradiol on glucose metabolism of postmenopausal women is evident during the oral but not the intravenous glucose administration. Maturitas 1997 Dec 15;28(2):163-7
(16) - Cagnacci A, Soldani R, Carriero PL, Paoletti AM, Fioretti P, Melis GB. Effects of low doses of transdermal 17 beta-estradiol on carbohydrate metabolism in postmenopausal women. J Clin Endocrinol Metab 1992 Jun;74(6):1396-400
(17) - Barrat J, Giboudeau J, Polonovski J, Bigel P, Fourcat C, Porta F, Leger D. [Comparison of the effects of orally or percutaneously administered estradiol on carbohydrates and lipids after the menopause].[Article in French] J Gynecol Obstet Biol Reprod (Paris) 1984;13(6):621-7
(18) - Colacurci N, Zarcone R, Mollo A, Russo G, Passaro M, de Seta L, de Franciscis P. Effects of hormone replacement therapy on glucose metabolism. Panminerva Med 1998 Mar;40(1):18-21
(19) - Kumagai S, Holmang A, Bjorntorp P. The effects of oestrogen and progesterone on insulin sensitivity in female rats. Acta Physiol Scand 1993 Sep;149(1):91-7
(20) - Puah JA, Bailey CJ. Effect of ovarian hormones on glucose metabolism in mouse soleus muscle. Endocrinology 1985 Oct;117(4):1336-40
(21) - Mayeaux EJ Jr, Johnson C. Current concepts in postmenopausal hormone replacement therapy. J Fam Pract 1996 Jul;43(1):69-75
(22) - Sherwin BB. Sex hormones and psychological functioning in postmenopausal women. Exp Gerontol 1994 May-Aug;29(3-4):423-30
(23) – Smith RNJ, Studd JWW. Estrogens and Depression in Women. IN: Lobo RA. Treatment of the Postmenopausal Woman, Basic and Clinical Aspects. Lippincott-Raven Publishers. 1996
(24) - Sherwin BB. Estrogen effects on cognition in menopausal women. Neurology 1997 May;48(5 Suppl 7):S21-6
(25) - Kampen DL, Sherwin BB. Estrogen use and verbal memory in healthy postmenopausal women. Department of Psychology, McGill University, Montreal, Quebec, Canada Obstet Gynecol 1994 Jun;83(6):979-83
(26) - Lipworth L, Adami HO, Trichopoulos D, Carlstrom K, Mantzoros C. Serum steroid hormone levels, sex hormone-binding globulin, and body mass index in the etiology of postmenopausal breast cancer. Epidemiology 1996 Jan;7(1):96-100
(27) - Grosman N, Hvidberg E, Schou J. The effect of oestrogenic treatment on the acid mucopolysaccharide pattern in skin of mice. Acta Pharmacol Toxicol (Copenh) 1971;30(5):458-64
(28) - Grosman N. Study on the hyaluronic acid-protein complex, the molecular size of hyaluronic acid and the exchangeability of chloride in skin of mice before and after oestrogen treatment. Acta Pharmacol Toxicol (Copenh) 1973;33(3):201-8
(29) - Brincat M, Moniz CJ, Studd JW, Darby A, Magos A, Emburey G, Versi E. Long-term effects of the menopause and sex hormones on skin thickness. Br J Obstet Gynaecol 1985 Mar;92(3):256-9
(30) - Mano H, Yuasa T, Kameda T, Miyazawa K, Nakamaru Y, Shiokawa M, Mori Y, Yamada T, Miyata K, Shindo H, Azuma H, Hakeda Y, Kumegawa M. Mammalian mature osteoclasts as estrogen target cells. Biochem Biophys Res Commun 1996 Jun 25;223(3):637-42
(31) - Hughes DE, Dai A, Tiffee JC, Li HH, Mundy GR, Boyce BF. Estrogen promotes apoptosis of murine osteoclasts mediated by TGF-beta. Nat Med 1996 Oct;2(10):1132-6
(32) - Yamaguchi M, Matsui T. Zinc enhancement of 17beta-estradiol's anabolic effect in osteoblastic MC3T3-E1 cells. Calcif Tissue Int 1997 Jun;60(6):527-32
(33) - Slootweg MC, Swolin D, Netelenbos JC, Isaksson OG, Ohlsson C. Estrogen enhances growth hormone receptor expression and growth hormone action in rat osteosarcoma cells and human osteoblast-like cells. J Endocrinol 1997 Oct;155(1):159-64
(34) - Stepan J, Formankova J, Masatova A, Michalsky M, Rosenova Z. [Comparison of the effectiveness of 17-beta-estradiol and calcitonin in women with postmenopausal bone loss].[Article in Czech] Cas Lek Cesk 1997 Apr 16;136(8):242-8
(35) - Heikkinen AM, Niskanen L, Yla-Herttuala S, Luoma J, Tuppurainen MT, Komulainen M, Saarikoski S. Postmenopausal hormone replacement therapy and autoantibodies against oxidized LDL. Maturitas 1998 Jun 3;29(2):155-61
(36) - Nasr A, Breckwoldt M. Estrogen replacement therapy and cardiovascular protection: lipid mechanisms are the tip of an iceberg. Gynecol Endocrinol 1998 Feb;12(1):43-59
(37) - Haines CJ, Chung TK, Masarei JR, Tomlinson B, Lau JT. An examination of the effect of combined cyclical hormone replacement therapy on lipoprotein(a) and other lipoproteins. Atherosclerosis 1996;119(2):215-22.
(38) - Espeland MA, Marcovina SM, Miller V, Wood PD, Wasilauskas C, Sherwin R, Schrott H, Bush TL. Effect of postmenopausal hormone therapy on lipoprotein(a) concentration. PEPI Investigators. Postmenopausal Estrogen/Progestin Interventions. Circulation 1998 Mar 17;97(10):979-86