title: Alteration in serum leptin correlates with alterations in serum N-telopeptide of collagen type I and serum osteocalcin during the progression of osteoporosis in ovariectomized rats.
abstract: The role of leptin during the progression of osteoporosis was investigated in ovariectomized rats by correlation of serum leptin levels with N-telopeptide of collagen type I (NTx) and osteocalcin levels before ovariectomy and 20, 40 and 60 days after the operation. Furthermore, peripheral quantitative computed tomography was used to confirm the development of severe osteoporosis in rats on day 60. The levels of NTx and osteocalcin were significantly increased on day 20 [61.9+/-5.4 nM BCE (bone collagen equivalents) and 215.6+/-53.3 ng/mL, respectively] in comparison to those before ovariectomy (41.3+/-1.7 nM BCE and 60.4+/-10.9 ng/mL). Accordingly, leptin was significantly elevated on day 20 (3033+/-661 vs. 606+/-346 pg/mL before ovariectomy). Bone markers and leptin levels remained constant up to day 40, while a slight, but not statistically significant, decrease was noted for osteocalcin and leptin on day 60. Although leptin and bone markers did not correlate before ovariectomy (r=0.09 for NTx and r=-0.05 for osteocalcin), strong correlation was observed at all time points after ovariectomy. The data obtained suggest that the alterations in serum leptin levels during the progression of osteoporosis in ovariectomized rats follow the alterations in bone markers.
authors.affiliation: Department of Anatomy, Medical School, University of Patras, and Department of Pediatrics, Patras University Hospital, Greece.
authors.forename: Anastasia
authors.initials: A
authors.lastname: Stavropoulou
authors.forename: Gina E
authors.initials: GE
authors.lastname: Christopoulou
authors.forename: George
authors.initials: G
authors.lastname: Anastassopoulos
authors.forename: Sofia D
authors.initials: SD
authors.lastname: Panteliou
authors.forename: George P
authors.initials: GP
authors.lastname: Lyritis
authors.forename: Bessie E
authors.initials: BE
authors.lastname: Spiliotis
authors.forename: Nikos K
authors.initials: NK
authors.lastname: Karamanos
authors.forename: Elias
authors.initials: E
authors.lastname: Panagiotopoulos
authors.forename: Elias
authors.initials: E
authors.lastname: Lambiris
mesh_terms: D000818:Animals; D015415:Biomarkers / Q000097:blood; D001842:Bone and Bones / Q000378:metabolism; D003094:Collagen / Q000097:blood*; D024042:Collagen Type I / Q000097:blood*; D005260:Female; D020738:Leptin / Q000097:blood*; D015675:Osteocalcin / Q000097:blood*; D010024:Osteoporosis / Q000097:blood*; D010052:Ovariectomy / Q000009:adverse effects*; D010455:Peptides / Q000097:blood*; D051381:Rats; D013997:Time Factors; D014057:Tomography, X-Ray Computed / Q000379:methods
chemical_list: D015415:Biomarkers; D024042:Collagen Type I; D020738:Leptin; D010455:Peptides; C052929:collagen type I trimeric cross-linked peptide; D015675:Osteocalcin; D003094:Collagen