Abstract
Estrogen replacement therapy is reported to reduce the incidence of vertebral fractures in postmenopausal women, however, its compliance is limited because of side effects and safety concerns. Estrogen’s side effects on breast and uterine tissues leading to the potential increased risk of uterine and breast cancer limit widespread estrogen usage. Thus, there is a significant medical need for a therapy that protects against postmenopausal bone loss but is free of estrogen’s negative effects on reproductive tissues. Selective estrogen receptor modulators (SERMs) have been investigated as an alternative to hormone replacement therapy. One such compound, raloxifene, has been approved for the prevention and treatment of osteoporosis.
Lasofoxifene (LAS), a new, nonsteroidal, and potent SERM, is an estrogen antagonist or agonist depending on the target tissue. LAS selectively binds with high affinity to human estrogen receptors. In ovariectomized (OVX) rat studies, LAS prevented the decrease in femoral bone mineral density, tibial and lumbar vertebral trabecular bone mass at an ED100 of about 60 μg/kg/day. LAS inhibited the activation of trabecular and endocortical bone resorption and bone turnover in tibial metaphyses and diaphyses, and lumbar vertebral body in OVX rats. In addition, LAS decreased total serum cholesterol, inhibited body weight gain and increased soleus muscle weight in OVX rats. Similarly, LAS prevented bone loss induced by orchidectomy or aging in male rats by decreasing bone resorption and bone turnover while it had no effect in the prostate. Further, LAS decreased total serum cholesterol in intact aged male rats or in orchidectomized male rats. Synergestic skeletal effects were found with LAS in combination with bone anabolic agents such as prostaglandin E2 (PGE2), parathyroid hormone (PTH) or a growth hormone secretagoue (GHS) in OVX rats. In combination with estrogen, LAS inhibited the uterine stimulating effects of estrogen but did not block the bone protective effects of estrogen. In immature and aged female rats, LAS did not affect the uterine weight and uterine histology. In OVX adult female rats, LAS slightly but significantly increased uterine weight. These results demonstrated that LAS produced effects on the skeleton indistinguishable from estrogen in female and male rats. However, unlike estrogen, LAS had little effect on uterine weight and cellular proliferation of uterus in female rats. In preclinical anti-tumor studies, LAS inhibited human breast cancer growth in mice bearing MCF7 tumors, prevented NMU-induced mammary carcinomas and possessed chemotherapeutic effects in NMU-induced carcinomas in rats.
Therefore, we conclude that LAS possesses the antiestrogenic effects in breast tissue and estrogenic effects in bone and serum cholesterol, but lacks estrogen’s side effects on uterine tissue. These data support the therapeutic potential of LAS for the prevention and treatment of postmenopausal bone loss and mammary carcinomas in humans.
Full Text
The Full Text of this article is available as a PDF (1.3 MB).
References
- 1.Melton L.J., III, Chrischilles E.A., Cooper C., Lane A.W., Riggs B.L. How many women have osteoporosis? J. Bone Miner. Res. 1992;7:1005–1010. doi: 10.1002/jbmr.5650070902. [DOI] [PubMed] [Google Scholar]
- 2.Berg, R.L., Casell, J.S. (eds) Osteoporosis. The second fifty years: promoting health and preventing disability. National Academy Press, Washington DC, 1990, p.76–100. [PubMed]
- 3.Kessenich C.R., Rosen C.J. The pathophysiology of osteoporosis. In: Rosen C.J., editor. Osteoporosis: Diagnostic and Therapeutic Principles. Totowa, New Jersey: Humana Press Inc.; 1996. pp. 47–63. [Google Scholar]
- 4.Turner R.T., Riggs B.L., Spelsberg T.C. Skeletal effects of estrogen. Endocrine Rev. 1994;15:275–300. doi: 10.1210/er.15.3.275. [DOI] [PubMed] [Google Scholar]
- 5.Slemenda C.W., Longcope C., Zhou L., Hui S.L., Peacock M., Johnston C.C. Sex steroids and bone mass in older men. J. Clin. Invest. 1997;100:1755–1759. doi: 10.1172/JCI119701. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 6.Greendale G.A., Edelstein S., Barrett-Connor E. Endogenous sex steroids and bone mineral density in older women and men: the Rancho Bernardo study. J. Bone Miner. Res. 1997;12:1833–1843. doi: 10.1359/jbmr.1997.12.11.1833. [DOI] [PubMed] [Google Scholar]
- 7.Khosla S., Melton L.J., III, Atkinson E.J., O’Fallon W.M., Klee G.G., Riggs B.L. Relationship of serum sex steroid levels and bone turnover markers with bone mineral density in men and women: a key role for bioavailable estrogen. J. Clin. Endocronol. Metab. 1998;83:2266–2274. doi: 10.1210/jc.83.7.2266. [DOI] [PubMed] [Google Scholar]
- 8.Riggs B.L., Khosla S., Melton L.J., III A unitary model for involutional osteoporosis: estrogen deficiency causes both type I and type II osteoporosis in postmenopausal women and contributes to bone loss in aging men. J. Bone Miner. Res. 1998;13:763–773. doi: 10.1359/jbmr.1998.13.5.763. [DOI] [PubMed] [Google Scholar]
- 9.Kanis J.A., Melton L.J., III, Christiansen C., Johnson C.C., Khaltaev N. The diagnosis of osteoporosis. J. Bone Miner. Res. 1994;9:1137–1141. doi: 10.1002/jbmr.5650090802. [DOI] [PubMed] [Google Scholar]
- 10.Riggs B.L., Melton L.J., III The prevention and treatment of osteoporosis. N. Engl. J. Med. 1992;327:620–627. doi: 10.1056/NEJM199208273270908. [DOI] [PubMed] [Google Scholar]
- 11.Cauley J.A., Seeley D.G., Ensrud K., Ettinger B., Black D., Cummings S.R. Estrogen replacement therepy and fractures in older women. Annals Inter. Med. 1995;122:9–16. doi: 10.7326/0003-4819-122-1-199501010-00002. [DOI] [PubMed] [Google Scholar]
- 12.Lobo A. Benefits and risks of estrogen replacement therapy. Am. J. Obstet. Gynecol. 1995;173:982–990. doi: 10.1016/0002-9378(95)90247-3. [DOI] [PubMed] [Google Scholar]
- 13.Maxim P., Ettinger B., Spitalny G.M. Fracture protection provided by long-term estrogen treatment. Osteoporosis Int. 1995;5:23–29. doi: 10.1007/BF01623654. [DOI] [PubMed] [Google Scholar]
- 14.Whitehead M.I., Fraser D. Controversies concerning the safety of estrogen replacement therapy. Am. J. Ob. Gyn. 1987;156:1313–1322. doi: 10.1016/0002-9378(87)90170-0. [DOI] [PubMed] [Google Scholar]
- 15.Colditz G.A., Hankinson S.E., Hunter D.J., Wiliett W.C., Manson J.E., Stampfer M.J., Hennekens C., Rosner B., Speizer F.E. The use of estrogen and progestins and the risk of breast cancer in postmenopausal women. N. Eng. J. Med. 1995;332:1589–1593. doi: 10.1056/NEJM199506153322401. [DOI] [PubMed] [Google Scholar]
- 16.Love R.R., Bardon H.S., Mazess R.B., Epstein S., Chappell R.J. Effects of tamoxifen on lumbar spine bone mineral density in postmenopausal women after 5 years. Arch. Int. Med. 1994;154:2585–2588. doi: 10.1001/archinte.154.22.2585. [DOI] [PubMed] [Google Scholar]
- 17.Black L.J., Sato M., Rowley E.R., Magee D.E., Bekele A., Williams D.C., Gullinan G.J., Bendele R., Kauffman R.R., Bensch W.R., Frolik C.A., Termine J.D., Bryant H.U. Raloxifene (LY 139481 HCI) prevents bone loss and reduces serum cholesterol without causing uterine hypertrophy in ovariectomized rats. J. Clin. Invest. 1994;93:63–69. doi: 10.1172/JCI116985. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 18.Bryant H.U., Glasebrook A.L., Yang N.N., Sato M. A pharmacological review of raloxifene. J. Bone Miner. Metab. 1996;14:1–9. doi: 10.1007/BF01771666. [DOI] [Google Scholar]
- 19.Ke H.Z., Simmons H.A., Pirie C.M., Crawford D.T., Thompson D.D. Droloxifene, a new estrogen antagonist/agonist, prevents bone loss in ovariectomized rats. Endocrinology. 1995;136:2435–2441. doi: 10.1210/en.136.6.2435. [DOI] [PubMed] [Google Scholar]
- 20.Ke H.Z., Chen H.K., Simmons H.A., Qi H., Crawford D.T., Pirie C.M., Chidsey-Frink K.L., Ma Y.F., Jee W.S.S., Thompson D.D. Comparative effects of droloxifene, tamoxifen, and estrogen on bone, serum cholesterol, and uterine histology in the ovariectomized rat model. Bone. 1997;20:31–39. doi: 10.1016/S8756-3282(96)00313-4. [DOI] [PubMed] [Google Scholar]
- 21.Bryant H.U., Dere W.H. Selective estrogen receptor modulators: an alternative to hormone replacement therapy. Proce. Society Exp. Biol. Medicine. 1998;217:45–52. doi: 10.3181/00379727-217-44204. [DOI] [PubMed] [Google Scholar]
- 22.Johnston C.C., Bjarnason N.H., Cohen F.J., Shah A., Lindsay R., Mitlak B.H., Huster W., Draper M.W., Harper K.D., Heath H., Gennari C., Christiansen C., Arnaud C.D., Delmas P.D. Long-term effects of raloxifene on bone mineral density, bone turnover, and serum lipid levels in early postmenopausal women. Arch. Intern. Med. 2000;160:3444–34450. doi: 10.1001/archinte.160.22.3444. [DOI] [PubMed] [Google Scholar]
- 23.Ettinger B., Black D.M., Knickerbocker R.K., Nickelsen T., Genant H.K., Christiansen C., Delmas P.D., Zanchetta J.R., Stakkestad J., Gluer C.C., Krueger K., Cohen E.J., Eckert S., Ensrud K.E., Avioli L.V., Lips P., Cummings S. Reduction of vertebral fracture risk in postmenopausal women with osteoporosis treated with raloxifene. JAMA. 1999;282:637–645. doi: 10.1001/jama.282.7.637. [DOI] [PubMed] [Google Scholar]
- 24.Cummings S., Eckert S., Krueger K., Grady D., Powles T.J., Cauley J.A., Norton L., Nickelsen T., Bjarnason N.H., Morrow M., Lippman M.E., Black D.M., Glusman J.E., Costa A., Jordan V.G. The effects of raloxifene on risk of breast cancer in postmenopausal women. JAMA. 1999;281:2189–2197. doi: 10.1001/jama.281.23.2189. [DOI] [PubMed] [Google Scholar]
- 25.Agnusdei D., Compston J. SERMs, a novel option to maintain health in the postmenopause. London, UK: Martin Dunitz Ltd; 2000. pp. 49–61. [Google Scholar]
- 26.McDonnell D.P. Selective estrogen receptor modulators (SERMs): a first step in the development of perfect hormone replacement therapy regimen. J. Soc. Gynecol. Investig. 2000;7:S10–S15. doi: 10.1016/S1071-5576(99)00055-6. [DOI] [PubMed] [Google Scholar]
- 27.Ke H.Z., Paralkar V.M., Grasser W.A., Crawford D.T., Qi H., Simmons H.A., Pirie C.M., Chidsey-Frink K.L., Owen T.A., Smock S.L., Chen H.K., Jee W.S.S., Cameron K.O., Rosati R.L., Brown T.A., DaSilva-Jardine P., Thompson D.D. Effects of CP-336,156, a new, nonsteroidal estrogen agonist/antagonist, on bone, serum cholesterol, uterus, and body composition in rat models. Endocrinology. 1998;139:2068–2076. doi: 10.1210/en.139.4.2068. [DOI] [PubMed] [Google Scholar]
- 28.Ke H.Z., Qi H., Crawford D.T., Chidsey-Frink K.L., Simmons H.A., Thompson D.D. Lasofoxifene (CP-336,156), a selective estrogen receptor modulator, prevents bone loss induced by aging and orchidectomy in the adult rat. Endocrinology. 2000;141:1338–1344. doi: 10.1210/en.141.4.1338. [DOI] [PubMed] [Google Scholar]
- 29.Ke H.Z., Qi H., Chidsey-Frink K.L., Crawford D.T., Thompson D.D. Lasofoxifene (CP-336,156) protects against the age-related changes in bone mass, bone strength, and total serum cholesterol in intact aged male rats. J. Bone Miner. Res. 2001;16:765–773. doi: 10.1359/jbmr.2001.16.4.765. [DOI] [PubMed] [Google Scholar]
- 30.Cohen L.A., Pittman B., Wang C.-X., Aliaga C., Yu L., Moyer J.D. LAS, a novel selective estrogen receptor modulator with chemopreventive and therapeutic activity in the N-methylurea-induced rat mammary tumor model. Cancer Research. 2001;61:8683–8688. [PubMed] [Google Scholar]
- 31.Petersen D. N., Tkalcevic G.T., Koza-Taylor P.H., Tud T.G., Brown T.A. Identification of estrogen receptor beta2, a functional variant of estrogen receptor beta expressed in normal rat tissues. Endocrinology. 1998;139:1082–92. doi: 10.1210/en.139.3.1082. [DOI] [PubMed] [Google Scholar]
- 32.Leake R.E., Habib F. Steroid hormone receptors: assay and characterization. In: Green B., Leake R.E., editors. Steroid Hormones: A Practical Approach. Oxford: IRL Press Ltd.; 1987. pp. 67–92. [Google Scholar]
- 33.Wijayaratne A.L., Nagel S.C., Paige L.A., Christensen D.J., Norris J.D., Fowlkes D.M., McDonnell D.P. Comparative analyses of mechanistic differences among antiestrogens. Endocrinology. 1999;140:5828–40. doi: 10.1210/en.140.12.5828. [DOI] [PubMed] [Google Scholar]
- 34.Tzukerman M.T., Esty A., Santiso-Mere D., Danielian P., Parker M.G., Stein R.B., Pike J.W., McDonnell D.P. Human estrogen receptor transactivational capacity is determined by both cellular and promoter context and mediated by two functionally distinct intramolecular regions. Molecular Endocrinology. 1994;8:21–30. doi: 10.1210/me.8.1.21. [DOI] [PubMed] [Google Scholar]
- 35.McDonnell D.P., Clemm D.L., Hermann T., Goldman M.E., Pike J.W. Analysis of estrogen receptor function in vitro reveals three distinct classes of antiestrogens. Molecular Endocrinology. 1995;9:659–69. doi: 10.1210/me.9.6.659. [DOI] [PubMed] [Google Scholar]
- 36.O’Brien M.L., Park K., In Y., Park-Sarge O.K. Characterization of estrogen receptor-beta (ERbeta) messenger ribonucleic acid and protein expression in rat granulosa cells. Endocrinology. 1999;140:4530–41. doi: 10.1210/en.140.10.4530. [DOI] [PubMed] [Google Scholar]
- 37.Kalu D.N. The ovariectomized rat model of postmenopausal bone loss. Bone and Mineral. 1991;15:175–192. doi: 10.1016/0169-6009(91)90124-I. [DOI] [PubMed] [Google Scholar]
- 38.Wronski T. J., Yen C.-F. The ovariectomized rat model as an animal model for postmenopausal bone loss. Cells Materials, suppl. 1991;1:69–74. [Google Scholar]
- 39.Frost H.M., Jee W.S.S. On the rat model of human osteopenias and osteoporosis. Bone and Mineral. 1992;18:227–236. doi: 10.1016/0169-6009(92)90809-R. [DOI] [PubMed] [Google Scholar]
- 40.Jee W.S.S., Yao W. Overview: animal models of osteopenia and osteoporosis. J. Musculoskel. Neuron. Interact. 2001;1:193–207. [PubMed] [Google Scholar]
- 41.Chen H.K., Ke H.Z., Lin C.H., Ma Y.F., Qi H., Crawford D.T., Pirie C.M., Simmons H.A., Jee W.S.S., Thompson D.D. Droloxifene inhibits cortical bone turnover associated with estrogen deficiency in rats. Bone. 1995;17(suppl.):175S–179S. doi: 10.1016/8756-3282(95)00290-T. [DOI] [PubMed] [Google Scholar]
- 42.Ke H.Z., Chen H.K., Qi H., Pirie C.M., Simmons H.A., Ma Y.F., Jee W.S.S., Thompson D.D. Effects of Droloxifene on prevention of cancellous bone loss and bone turnover of the axial skeleton of aged, ovariectomized rats. Bone. 1995;17:491–496. doi: 10.1016/8756-3282(95)00346-2. [DOI] [PubMed] [Google Scholar]
- 43.Chen H.K., Ke H.Z., Jee W.S.S., Ma Y.F., Pirie C.M., Simmons H.A., Thompson D.D. Droloxifene Prevents ovariectomy-induced bone loss in tibiae and femora of aged female rats: a dual-energy x-ray absorptiometric and histomorphometric study. J. Bone and Miner. Res. 1995;10:1256–1262. doi: 10.1002/jbmr.5650100816. [DOI] [PubMed] [Google Scholar]
- 44.Guidelines for preclinical and clinical evaluation of agents used in the prevention or treatment of postmenopausal osteoporosis (draft). Division of Metabolism and Endocrine Drug Products, U. S. Food and Drug Administration, 1994.
- 45.Thompson D.D., Simmons H.A., Pirie C.M., Ke H.Z. FDA guidelines and animal models for ostecporosis. Bone. 1995;17(suppl.4):125S–133S. doi: 10.1016/8756-3282(95)00285-l. [DOI] [PubMed] [Google Scholar]
- 46.Dempster D.W., Cosman F., Parisien M., Shen V. Anabolic action of parathyroid hormone on bone. Endocrine Review. 1993;14:690–709. doi: 10.1210/er.14.6.690. [DOI] [PubMed] [Google Scholar]
- 47.Jee W.S.S., Ma Y.F. The in vivo anabolic actions of prostaglandins in bone. Bone. 1997;21:297–304. doi: 10.1016/S8756-3282(97)00147-6. [DOI] [PubMed] [Google Scholar]
- 48.Ke H.Z., Shen V.W., Qi H., Crawford D.T., Wu D.D., Liang X.G., Chidsey-Frink K.L., Pirie C.M., Simmons H.A., Thompson D.D. Prostaglandin E2 increases bone strength in intact rats and in ovariectomized rats with established osteopenia. Bone. 1998;23:249–255. doi: 10.1016/S8756-3282(98)00102-1. [DOI] [PubMed] [Google Scholar]
- 49.Ke H.Z., Crawford D.T., Qi H., Pirie C.M., Simmons H.A., Chidsey-Frink K.L., Chen H.K., Jee W.S.S., Thompson D.D. Droloxifene does not blunt the bone anabolic effects of prostaglandin E2 but maintains the prostaglandin E2-restored bone in aged, ovariectomized rats. Bone. 1999;24:41–47. doi: 10.1016/S8756-3282(98)00146-X. [DOI] [PubMed] [Google Scholar]
- 50.Ke H.Z., Chidsey-Frink K.L., Crawford D.T., Qi H., Simmons H.A., Thompson D.D. Co-treatment of lasofoxifene (CP-336,156) and estrogen inhibits estrogen’s effect in the uterus but maintains the bone protective effects in ovariectomized rats. J. Bone and Mineral Res. 2000;15(suppl.1):S310. [Google Scholar]
- 51.Ke H.Z., Chidsey-Frink K.L., Simmons H.A., Crawford D.T., Qi H., Pirie C.M., Shen V., Thompson D.D. CP-336,156, A New Selective Estrogen Receptor Modulator (SERM), Enhances the Effects of Parathyroid Hormone in Restoring Bone Mass and Strength in Ovariectomized Rats. J. Bone and Mineral Res. 1998;13(suppl.1):S495. [Google Scholar]
- 52.Ke H.Z., Crawford D.T., Qi H., Chidsey-Frink K.L., Pirie C.M., Simmons H.A., Shen V., Thompson D.D. CP-336,156, a New Selective Estrogen Receptor Modulator (SERM), Halts Further Bone Loss and Potentiates the Effects of Prostaglandin E2 (PGE2) in Restoring Bone Mass and Bone Strength in Ovariectomized Rats. J. Bone and Mineral Res. 1998;13(suppl.1):S609. [Google Scholar]
- 53.Ohlsson C., Bengtsson B.-A., Isaksson O.G.P., Andreassen T.T., Slootweg M.C. Growth hormone and bone. Endocrine Review. 1998;19:55–79. doi: 10.1210/er.19.1.55. [DOI] [PubMed] [Google Scholar]
- 54.Pan L.C., Carpino P.A., Lefker B.A., Ragan J.A., Toler S.M., Pettersen J.C., Nettleton D.C., Ng O.C., Pirie C.M., Chidsey-Frink K., Lu B., Nickerson D.F., Tess D.A., Mullins M.A., MacLean D.B., DaSilva-Jardine P.A., Thompson D.D. Pre-clinical pharmacology of CP-424391, an orally active pyazolidinone-piperidine growth hormone secretagogue. Endocrine. 2001;14:121–132. doi: 10.1385/ENDO:14:1:121. [DOI] [PubMed] [Google Scholar]
- 55.Ke H.Z., Li M., Pan L.C., Yu L., MacLean D.B., Thompson D.D. Combined administration of a growth hormone secretagogue (GHS) and a new selective estrogen receptor modulator (SERM) increases bone and muscle mass and decreases total serum cholesterol in ovariectomized rats. J. Bone and Mineral Res. 1998;13(suppl.1):S390. [Google Scholar]
- 56.Kanis J.A., Pitt F.A. Epidemiology of osteoporosis. Bone. 1992;13:S7–S15. doi: 10.1016/8756-3282(92)90189-4. [DOI] [PubMed] [Google Scholar]
- 57.Cooper C., Campion G., Melton L.J. Hip fractures in the elderly: a world-wide projection. Osteoporosis Int. 1992;2:285–289. doi: 10.1007/BF01623184. [DOI] [PubMed] [Google Scholar]
- 58.Slemenda C.W., Longcope C., Zhou L., Hui S.L., Peacock M., Johnston C.C. Sex steroids and bone mass in older men. J. Clin. Invest. 1997;100:1755–1759. doi: 10.1172/JCI119701. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 59.Greendale G.A., Edelstein S., Barrett-Connor E. Endogenous sex steroids and bone mineral density in older women and men: the Rancho Bernardo study. J. Bone Miner. Res. 1997;12:1833–1843. doi: 10.1359/jbmr.1997.12.11.1833. [DOI] [PubMed] [Google Scholar]
- 60.Khosla S., Melton L.J., III, Atkinson E.J., O’Fallon W.M., Klee G.G., Riggs B.L. Relationship of serum sex steroid levels and bone turnover markers with bone mineral density in men and women: a key role for bioavailable estrogen. J. Clin. Endocronol. Metab. 1998;83:2266–2274. doi: 10.1210/jc.83.7.2266. [DOI] [PubMed] [Google Scholar]
- 61.Riggs B.L., Khosla S., Melton L.J., III A unitary model for involutional osteoporosis: estrogen deficiency causes both type I and type II osteoporosis in postemenopausal women and contributes to bone loss in aging men. J. Bone Mineral Res. 1998;13:763–773. doi: 10.1359/jbmr.1998.13.5.763. [DOI] [PubMed] [Google Scholar]
- 62.Ke H.Z., Crawford D.T., Qi H., Chidsey-Frink K.L., Simmons H.A., Li M., Jee W.S.S., Thompson D.D. Long-term effects of aging and orchidectomy on bone and body composition in rapidly growing male rats. J. Musculoskel. Neuron. Interact. 2001;1:215–224. [PubMed] [Google Scholar]
- 63.Erben R.G., Eberle J., Stahr K., Goldberg M. Androgen deficiency induces high turnover osteopenia in aged male rats: a sequential histomorphometric study. J. Bone Miner. Res. 2000;15:1085–1098. doi: 10.1359/jbmr.2000.15.6.1085. [DOI] [PubMed] [Google Scholar]
- 64.Wakley G.K., Schutt H.D., Hannon K.S., Turner R.T. Androgen treatment prevents loss of cancellous bone in the orchidectomized rats. J. Bone Miner. Res. 1991;6:325–330. doi: 10.1002/jbmr.5650060403. [DOI] [PubMed] [Google Scholar]
- 65.Vanderscheuren D., Van Herck D., Suiker A.M.H., Visser W.J., Schot L.P.C., Bouillon R. Bone and mineral metabolism in aged male rats: short and long term effects of androgen deficiency. Endocrinology. 1992;130:2906–2916. doi: 10.1210/en.130.5.2906. [DOI] [PubMed] [Google Scholar]
- 66.Li M., Jee W.S.S., Ke H.Z., Tang L.Y., Ma Y.F., Liang X.G., Setterberg R.B. Prostaglandin E2 administration prevents bone loss induced by orchidectomy in rats. J. Bone Miner. Res. 1995;10:66–73. doi: 10.1002/jbmr.5650100111. [DOI] [PubMed] [Google Scholar]
- 67.Fisher B., Costantino J.P., Wickerham D.L., Redmond C.K., Kavanah M., Cronin W.M., Vogel V., Robidoux A., Dimitrov N., Atkins J., Daly M., Wieand S., Tan-Chiu E., Ford L., Wolmark N. Tamoxifen for prevention of breast cancer: report of the National Surgical Adjuvant Breast and Bowel Project P-1 study. J. Natl. Cancer Inst. (Bethesda) 1998;90:1371–1388. doi: 10.1093/jnci/90.18.1371. [DOI] [PubMed] [Google Scholar]