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Expression and distribution of heme oxygenase‐1 and ‐2 in rat brown adipose tissue: the modulatory role of the noradrenergic system
Author(s) -
Giordano Antonio,
Nisoli Enzo,
Tonello Cristina,
Cancello Raffaella,
Carruba Michele O,
Cinti Saverio
Publication year - 2000
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(00)02217-1
Subject(s) - brown adipose tissue , heme oxygenase , blot , cytosol , gene isoform , adipose tissue , cytoplasm , medicine , endocrinology , heme , messenger rna , biology , chemistry , microbiology and biotechnology , biochemistry , enzyme , gene
To investigate whether brown adipose tissue (BAT) expresses the inducible (HO‐1) and the constitutive (HO‐2) isoform of heme oxygenase, reverse transcriptase‐polymerase chain reaction, Western blotting and immunohistochemistry were performed on interscapular BAT (IBAT) from rats acclimated at environmental temperature or exposed to cold. Both HO isoforms were detected in rat IBAT. They were immunolocalized in the cytoplasm and/or nuclei of brown adipocytes, in parenchymal capillaries, arteries and in some veins and nerves. Whereas cold exposure did not affect HO‐2 expression, it significantly increased the expression of HO‐1, both at mRNA (about 3‐fold) and protein (about 2‐fold) levels, reflecting the increased expression of HO‐1 in the brown adipocytes and endothelial cells of parenchymal capillaries. Western blotting of cytosolic and nuclear protein extracts from cultured differentiated brown adipocytes showed that HO‐1 and HO‐2 are indeed localized in the cytosol and nuclei of brown adipocytes, and that noradrenaline stimulation significantly increased their amount in cytosol but not in the nuclear fraction.