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Leptin Is Expressed in and Secreted from Primary Cultures of Human Osteoblasts and Promotes Bone Mineralization
Author(s) -
Reseland Janne E.,
Syversen Unni,
Bakke Ingunn,
Qvigstad Gunnar,
Eide Liv G.,
Hjertner Øyvind,
Gordeladze Jan O.,
Drevon Christian A.
Publication year - 2001
Publication title -
journal of bone and mineral research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.882
H-Index - 241
eISSN - 1523-4681
pISSN - 0884-0431
DOI - 10.1359/jbmr.2001.16.8.1426
Subject(s) - leptin , leptin receptor , medicine , endocrinology , adipose tissue , chemistry , cell culture , mineralization (soil science) , biology , genetics , obesity , organic chemistry , nitrogen
The adipose hormone leptin and its receptor are important for regulation of food intake and energy metabolism. Leptin also is involved in the growth of different tissues. In this study, we show the expression of leptin in primary cultures of normal human osteoblasts (hOBs) as evidenced by reverse transcriptase‐polymerase chain reaction (RT‐PCR) and immunocytochemistry. Release of leptin into the medium also was found. Leptin was not detected in commercially available hOBs (NHOst) or in three different human monoclonal osteosarcoma cell lines. Leptin expression was observed in OBs in the mineralization and/or the osteocyte transition period but not during the matrix maturation period. Furthermore, hOBs and osteosarcoma cell lines expressed the long signal‐transducing form of the leptin receptor (OB‐Rb) as shown by RT‐PCR. We observed no significant changes in leptin or OB‐Rb genes in hOBs after incubation with recombinant leptin, indicating no autoregulation of the leptin expression. Incubation of both hOBs entering the mineralization phase and osteosarcoma cell lines with recombinant leptin markedly increased the number of mineralized nodules as shown by alizarin S staining. These findings indicate that leptin may be of importance for osteoblastic cell growth and bone mineralization.