This Article Full Text Full Text (PDF) Submit a related Letter to the Editor Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Copyright Permission Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Glasow, A. Articles by Kratzsch, J. Search for Related Content PubMed PubMed Citation Articles by Glasow, A. Articles by Kratzsch, J.

Expression of Leptin (Ob) and Leptin Receptor (Ob-R) in Human Fibroblasts: Regulation of Leptin Secretion by Insulin

Institute of Laboratory Medicine, Clinical Chemistry, and Molecular Diagnostics (A.G., J.K.), and Department of Dermatology, University of Leipzig (U.A.), 04103 Leipzig, Germany; and Children’s Hospital (A.G., W.K., A.Be., A.Bo.), 04317 Leipzig, Germany

Address all correspondence and requests for reprints to: J. Kratzsch, Ph.D., Institute of Laboratory Medicine, Clinical Chemistry, and Molecular Diagnostics, University of Leipzig, Liebigstrasse 27, D-04103 Leipzig, Germany. E-mail: kraj{at}medizin.uni-leipzig.de

Abstract

Leptin, a hormone of the cytokine family, is mainly synthesized by white adipocytes. As fibroblasts and adipocytes share a common stem cell origin, we hypothesized that connective tissue may be another candidate for leptin synthesis. We demonstrated leptin receptors, inclusive of all isoforms, on cultured fibroblasts (n = 13) by RT-PCR and immunohistochemistry. In contrast to its receptor, basal leptin mRNA expression and protein secretion were found in 8 of 13 cultures, reaching 1.4 ng/350,000 cells·24 h. Incubation with physiological insulin concentrations (1 nmol/liter) increased leptin secretion in fibroblast culture supernatants to 152% of basal levels. A maximal stimulation of the basal level up to 192% was found with 10 nmol/liter insulin after 24 h. Actinomycin D and cycloheximide abolished this effect, providing evidence that active RNA and protein synthesis are involved in insulin’s action. Completing these in vitro results, we could show protein expression for leptin and leptin receptors in fibroblasts by immunostaining of human skin biopsies in situ. In conclusion, we provide evidence of leptin synthesis and secretion by human fibroblasts that are regulated by insulin. Leptin produced by fibroblasts may thus exert important local autocrine and paracrine actions and contribute to the total plasma pool. Hence it might in part account for variations in body mass index-dependent reference ranges of leptin as well as disruptions in the relationship between fat content and leptin.

This article has been cited by other articles:

				M Bokarewa, D Bokarew, O Hultgren, and A Tarkowski Leptin consumption in the inflamed joints of patients with rheumatoid arthritis Ann Rheum Dis, October 1, 2003; 62(10): 952 - 956. [Abstract] [Full Text]

				T. Reimer, D. Koczan, B. Gerber, D. Richter, H.J. Thiesen, and K. Friese Microarray analysis of differentially expressed genes in placental tissue of pre-eclampsia: up-regulation of obesity-related genes Mol. Hum. Reprod., July 1, 2002; 8(7): 674 - 680. [Abstract] [Full Text] [PDF]

				M. Shintani, H. Ikegami, T. Fujisawa, Y. Kawaguchi, M. Ohishi, T. Katsuya, J. Higaki, K. Shimamoto, and T. Ogihara Leptin Gene Polymorphism Is Associated with Hypertension Independent of Obesity J. Clin. Endocrinol. Metab., June 1, 2002; 87(6): 2909 - 2912. [Abstract] [Full Text] [PDF]