title: Leptin protects the cardiac myocyte cultures from hypoxic damage.
abstract: Leptin, a circulating hormone mainly produced by adipose tissue, regulates fatty acid metabolism and causes multiple systemic biological actions even the regulation of cardiovascular function. It is previously known that leptin is a hypoxia-inducible hormone, that hypoxic conditions increase the expression of this peptide in various tissues such as placenta, pancreas and also in the heart. Since leptin receptors are present in the heart, we hypothesized that whether leptin was a protector response for tissues especially for the heart against the deleterious effects of hypoxia. Cultured cardiomyocytes from newborn rats were initially treated with 3000 ng/ml leptin incubation for 1, 5 and 20 h separately, then subjected to 120 min of hypoxia. Hypoxic damage of myocytes was assayed using the measurements of both lactate dehydrogenase and creatine kinase releases into the medium and performing morphological observations (ultrastructural and immunocytochemical) of plates. The obtained results from leptin treated and non-treated control groups were compared to each other, and these data have demonstrated that 5 h of leptin treatment before hypoxia provides a significant protection for cardiomyocytes against hypoxia. Neither 1- nor 20-h leptin treated groups exhibited sufficient protection against hypoxia. In conclusion, leptin protects the cardiomyocyte cultures from hypoxia, but this effect is selective and evident only in the 5-h treated myocytes.
authors.affiliation: Osmangazi University, School of Medicine, Physiology Department, Eskisehir, Turkey.
authors.forename: Nilufer
authors.initials: N
authors.lastname: Erkasap
authors.forename: Murat
authors.initials: M
authors.lastname: Ikizler
authors.forename: Vladimir
authors.initials: V
authors.lastname: Shneyvays
authors.forename: Tova
authors.initials: T
authors.lastname: Zinman
authors.forename: Liaman K
authors.initials: LK
authors.lastname: Mamedova
authors.forename: Ruhi
authors.initials: R
authors.lastname: Uyar
authors.forename: Asher
authors.initials: A
authors.lastname: Shainberg
mesh_terms: D000818:Animals; D015687:Cell Hypoxia / Q000187:drug effects* / Q000502:physiology*; D002478:Cells, Cultured; D003402:Creatine Kinase / Q000097:blood; D003470:Culture Media; D003893:Desmin / Q000494:pharmacology; D007150:Immunohistochemistry; D007770:L-Lactate Dehydrogenase / Q000097:blood; D020738:Leptin / Q000494:pharmacology*; D032383:Myocytes, Cardiac / Q000187:drug effects* / Q000201:enzymology / Q000648:ultrastructure; D051381:Rats
chemical_list: D003470:Culture Media; D003893:Desmin; D020738:Leptin; D007770:L-Lactate Dehydrogenase; D003402:Creatine Kinase