Effect of Ovariectomy on Adipose Tissue of Mice in the Absence of Estrogen Receptor Alpha (ERα): a Potential Role for Estrogen Receptor Beta (ERβ)

Abstract

Adipose tissue deposition is highly responsive to estrogen; ovariectomy increases adipose deposition, and estrogen replacement reverses this. Estrogen receptor α (ERα) plays a major role in adipose tissue. ERα knockout (αERKO) mice show an increase in adipose tissue of over a 100 % compared to wild-type mice. However, αERKO mice undergo a 10-fold increase in 17β-estradiol (E2), and persistent or even increased signaling through ERβ could be a factor in obesity of αERKO mice. To test the hypothesis that ERβ plays a role in adipose tissue, adult female αERKO mice were ovariectomized or sham-ovariectomized and fed a phytoestrogen-free diet. Ovariectomized mice were treated with vehicle or E2, and bodyweights and food consumption were measured. Mice were killed after 28 days and inguinal and parametrial fat pads collected. Sham-ovariectomized αERKO mice had increased body weight, ovariectomized αERKO mice showed a 6 % decrease, and E2 replacement restored body weight to sham levels. Fat pads of ovariectomized αERKO mice showed 45 % and 16 % decreases in weight and adipocyte circumference, respectively, compared to sham-ovariectomized or E2-replaced ovariectomized αERKO mice. Ovariectomized αERKO mice showed a trend towards decreased feed consumption that did not reach significance. Blood glucose levels were lower both before and after glucose injection in ovariectomized compared to sham αERKO mice, and E2 treatment reversed this. Insulin levels following glucose challenge were lower in ovariectomized compared to sham-ovariectomized αERKO mice, indicating that ovariectomy ameliorated the glucose intolerance and insulin resistance in αERKO mice. Immunohistochemical analysis revealed strong staining for ERβ in adipose tissue. These observations indicate that removing E2/ERβ signaling in αERKO mice by ovariectomy decreases body and fat-pad weights and adipocyte size, while improving insulin and glucose metabolism. ERβ mediated effects on adipose tissue are opposite those of ERα, although E2 effects on adipose tissue are predominately through ERα.

Key words

ERα Knockout - Adipocyte - Insulin Resistance - Glucose Tolerance

References

• 1 Pallier E, Aubert R, Lemonnier D. Effect of diet and ovariectomy on adipose tissue cellularity in mice.  Reprod Nutr Dev. 1980;  20 631-636
• 2 Tonkelaar I D, Seidell J C, van Noord P A, Baanders-van H alewijn, Jacobus J H, Bruning P F. Factors influencing waist/hip ratio in randomly selected pre- and post-menopausal women in the dom-project (preliminary results).  Int J Obes. 1989;  13 817-824
• 3 Mohamed M K, Abdel-Rahman A A. Effect of long-term ovariectomy and estrogen replacement on the expression of estrogen receptor gene in female rats.  Eur J Endocrinol. 2000;  142 307-314
• 4 Pedersen S B, Borglum J D, Moller-Pedersen T, Richelsen B. Effects of in vivo estrogen treatment on adipose tissue metabolism and nuclear estrogen receptor binding in isolated rat adipocytes.  Mol Cell Endocrinol. 1992;  85 13-19
• 5 Gambacciani M, Ciaponi M, Cappagli B, Piaggesi L, de Simone L, Orlandi R, Genazzani A R. Body weight, body fat distribution, and hormonal replacement therapy in early postmenopausal women.  J Clin Endocrinol Metab. 1997;  82 414-417
• 6 Haarbo J, Marslew U, Gotfredsen A, Christiansen C. Postmenopausal hormone replacement therapy prevents central distribution of body fat after menopause.  Metabolism. 1991;  40 1323-1326
• 7 Wade G N, Gray J M, Bartness T J. Gonadal influences on adiposity.  Int J Obes. 1985;  9 Suppl. 1 83-92
• 8 Hamosh M, Hamosh P. The effect of estrogen on the lipoprotein lipase activity of rat adipose tissue.  J Clin Invest. 1975;  55 1132-1135
• 9 Pedersen S B, Bruun J M, Hube F, Kristensen K, Hauner H, Richelsen B. Demonstration of estrogen receptor subtypes alpha and beta in human adipose tissue: influences of adipose cell differentiation and fat depot localization.  Mol Cell Endocrinol. 2001;  182 27-37
• 10 Heine P A, Taylor J A, Iwamoto G A, Lubahn D B, Cooke P S. Increased adipose tissue in male and female estrogen receptor-alpha knockout mice.  Proc Natl Acad Sci USA. 2000;  97 12 729-12 734
• 11 Jones M E, Thorburn A W, Britt K L, Hewitt K N, Wreford N G, Proietto J, Oz O K, Leury B J, Robertson K M, Yao S, Simpson E R. Aromatase-deficient (ArKO) mice have a phenotype of increased adiposity.  Proc Natl Acad Sci USA. 2000;  97 12 735-12 740
• 12 Danilovich N, Babu P S, Xing W, Gerdes M, Krishnamurthy H, Sairam M R. Estrogen deficiency, obesity, and skeletal abnormalities in follicle-stimulating hormone receptor knockout (FORKO) female mice.  Endocrinology. 2000;  141 4295-4308
• 13 Couse J F, Korach K S. Estrogen receptor null mice: what have we learned and where will they lead us?.  Endocr Rev. 1999;  20 358-417
• 14 Lubahn D B, Moyer J S, Golding T S, Couse J F, Korach K S, Smithies O. Alteration of reproductive function but not prenatal sexual development after insertional disruption of the mouse estrogen receptor gene.  Proc Natl Acad Sci USA. 1993;  90 11 162-11 166
• 15 Saunders P T, Maguire S M, Gaughan J, Millar M R. Expression of oestrogen receptor beta (ER beta) in multiple rat tissues visualised by immunohistochemistry.  J Endocrinol. 1997;  154 R13-R16
• 16 Norton A J, Jordan S, Yeomans P. Brief, high-temperature heat denaturation (pressure cooking): a simple and effective method of antigen retrieval for routinely processed tissues.  J Pathol. 1994;  173 371-379
• 17 Das S K, Taylor J A, Korach K S, Paria B C, Dey S K, Lubahn D B. Estrogenic responses in estrogen receptor-alpha deficient mice reveal a distinct estrogen signaling pathway.  Proc Natl Acad Sci USA. 1997;  94 12 786-12 791
• 18 Weihua Z, Saji S, Makinen S, Cheng G, Jensen E V, Warner M, Gustafsson J A. Estrogen receptor (ER) beta, a modulator of ERalpha in the uterus.  Proc Natl Acad Sci USA. 2000;  97 5936-5941
• 19 Hall J M, McDonnell D P. The estrogen receptor beta-isoform (ERbeta) of the human estrogen receptor modulates ERalpha transcriptional activity and is a key regulator of the cellular response to estrogens and antiestrogens.  Endocrinology. 1999;  140 5566-5578
• 20 Roy E J, Wade G N. Role of food intake in estradiol-induced body weight changes in female rats.  Horm Behav. 1977;  8 265-274
• 21 Liang Y Q, Akishita M, Kim S, Ako J, Hashimoto M, Iijima K, Ohike Y, Watanabe T, Sudoh N, Toba K, Yoshizumi M, Ouchi Y. Estrogen receptor ss is involved in the anorectic action of estrogen.  Int J Obes Relat Metab Disord. 2002;  26 1103-1109
• 22 Eng R, Gold R M, Wade G N. Ovariectomy-induced obesity is not prevented by subdiaphragmatic vagotomy in rats.  Physiol Behav. 1979;  22 353-356
• 23 Olefsky J M, Reaven G M. Effects of age and obesity on insulin binding to isolated adipocytes.  Endocrinology. 1975;  96 1486-1498
• 24 Pedersen S B, Hansen P S, Lund S, Andersen P H, Odgaard A, Richelsen B. Identification of oestrogen receptors and oestrogen receptor mRNA in human adipose tissue.  Eur J Clin Invest. 1996;  26 262-269
• 25 Anwar A, McTernan P G, Anderson L A, Askaa J, Moody C G, Barnett A H, Eggo M C, Kumar S. Site-specific regulation of oestrogen receptor-alpha and -beta by oestradiol in human adipose tissue.  Diabetes Obes Metab. 2001;  3 338-349
• 26 Kuiper G G, Carlsson B, Grandien K, Enmark E, Haggblad J, Nilsson S, Gustafsson J A. Comparison of the ligand binding specificity and transcript tissue distribution of estrogen receptors alpha and beta.  Endocrinology. 1997;  138 863-870
• 27 Paech K, Webb P, Kuiper G G, Nilsson S, Gustafsson J, Kushner P J, Scanlan T S. Differential ligand activation of estrogen receptors ERalpha and ERbeta at AP1 sites.  Science. 1997;  277 1508-1510
• 28 Maruyama S, Fujimoto N, Asano K, Ito A. Suppression by estrogen receptor beta of AP-1 mediated transactivation through estrogen receptor alpha.  J Steroid Biochem Mol Biol. 2001;  78 177-184
• 29 Zechner R, Strauss J, Frank S, Wagner E, Hofmann W, Kratky D, Hiden M, Levak-Frank S. The role of lipoprotein lipase in adipose tissue development and metabolism.  Int J Obes Relat Metab Disord. 2000;  24 Suppl 4 S53-S56
• 30 Homma H, Kurachi H, Nishio Y, Takeda T, Yamamoto T, Adachi K, Morishige K, Ohmichi M, Matsuzawa Y, Murata Y. Estrogen suppresses transcription of lipoprotein lipase gene. Existence of a unique estrogen response element on the lipoprotein lipase promoter.  J Biol Chem. 2000;  275 11 404-11 411
• 31 Geary N, Asarian L, Korach K S, Pfaff D W, Ogawa S. Deficits in E2-dependent control of feeding, weight gain, and cholecystokinin satiation in ER-alpha null mice.  Endocrinology. 2001;  142 4751-4757
• 32 Ohlsson C, Hellberg N, Parini P, Vidal O, Bohlooly M, Rudling M, Lindberg M K, Warner M, Angelin B, Gustafsson J A. Obesity and disturbed lipoprotein profile in estrogen receptor-alpha-deficient male mice.  Biochem Biophys Res Commun. 2000;  278 640-645
• 33 Lindberg M K, Alatalo S L, Halleen J M, Mohan S, Gustafsson J A, Ohlsson C. Estrogen receptor specificity in the regulation of the skeleton in female mice.  J Endocrinol. 2001;  171 229-236
• 34 Lindberg M K, Weihua Z, Andersson N, Moverare S, Gao H, Vidal O, Erlandsson M, Windahl S, Andersson G, Lubahn D B, Carlsten H, Dahlman-Wright K, Gustafsson J A, Ohlsson C. Estrogen receptor specificity for the effects of estrogen in ovariectomized mice.  J Endocrinol. 2002;  174 167-178