Estrogen receptor alpha, but not estrogen receptor beta, is involved in the regulation of the OPG/RANKL (osteoprotegerin/receptor activator of NF-kappa B ligand) ratio and serum interleukin-6 in male mice

• Published in: Journal of endocrinology Vol. 171; no. 3; pp. 425 - 433
• Main Authors: Lindberg, MK, Erlandsson, M, Alatalo, SL, Windahl, S, Andersson, G, Halleen, JM, Carlsten, H, Gustafsson, JA, Ohlsson, C
• Format: Journal Article
• Language: English
• Published: England BioScientifica 01.12.2001
• Subjects: Acid Phosphatase; Acid Phosphatase - blood; Animals; Biological Markers; Biomarkers - blood; blood; Bone Density; Bone Density - drug effects; Carrier Proteins; Cytoplasmic and Nuclear; drug effects; Estradiol; Estradiol - pharmacology; Estrogen; Estrogen Receptor alpha; Estrogen Receptor beta; Female; Glycoproteins; Glycoproteins - metabolism; Inbred C57BL; Interleukin-6; Interleukin-6 - blood; Isoenzymes; Isoenzymes - blood; Ligands; Male; MEDICAL AND HEALTH SCIENCES; MEDICIN OCH HÄLSOVETENSKAP; Membrane Glycoproteins; metabolism; Mice; Mice, Inbred C57BL; NF-kappa B; NF-kappa B - metabolism; Orchiectomy; Osteoprotegerin; Ovariectomy; pharmacology; physiology; RANK Ligand; Receptor Activator of Nuclear Factor-kappa B; Receptors; Receptors, Cytoplasmic and Nuclear - metabolism; Receptors, Estrogen - physiology; Receptors, Tumor Necrosis Factor - metabolism; Tartrate-Resistant Acid Phosphatase; Tumor Necrosis Factor
• ISSN: 0022-0795; 1479-6805
• DOI: 10.1677/joe.0.1710425

Estrogens are important for the male skeleton. Osteoprotegerin (OPG), receptor activator of NF-kappa B ligand (RANKL), interleukin-6 (IL-6), IL-1 and tumor necrosis factor alpha (TNFalpha) have been suggested to be involved in the skeletal effects of estrogen. We treated orchidectomized mice with estradiol for 2 weeks and observed a 143% increase in the trabecular bone mineral density of the distal metaphysis of femur that was associated with a decreased OPG/RANKL mRNA ratio in vertebral bone. A similar decreased OPG/RANKL ratio was also seen after estrogen treatment of ovariectomized female mice. The effect of estrogen receptor (ER) inactivation on the OPG/RANKL ratio was dissected by using intact male mice lacking ER alpha (ERKO), ER beta (BERKO) or both receptors (DERKO). The expression of OPG was increased in ERKO and DERKO but not in BERKO male mice, resulting in an increased OPG/RANKL ratio. Furthermore, serum levels of IL-6 and tartrate-resistant acid phosphatase 5b (TRAP 5b) were decreased in ERKO and DERKO, but not in BERKO male mice. These results demonstrate that ER alpha, but not ER beta, is involved in the regulation of the vertebral OPG/RANKL ratio, serum levels of IL-6 and TRAP 5b in male mice.