In vitro experiments suggest that stimulation of lipolysis by catecholamines in adipocytes depends on the energy status of these cells. We tested whether mitochondrial uncoupling proteins (UCPs) that control the efficiency of ATP production could affect lipolysis and noradrenaline signalling in white fat in vivo. The lipolytic effect of noradrenaline was lowered by ectopic UCP1 in white adipocytes of aP2-Ucp1 transgenic mice, overexpressing the UCP1 gene from the aP2 gene promoter, reflecting the magnitude of UCP1 expression, the impaired stimulation of cAMP levels by noradrenaline and the reduction of the ATP/ADP ratio in different fat depots. Thus only subcutaneous but not epididymal fat was affected. UCP1 also down-regulated the expression of hormone-sensitive lipase and lowered its activity, and altered the expression of trimeric G-proteins in adipocytes. The adipose tissue content of the stimulatory G-protein alpha subunit was increased while that of the inhibitory G-protein alpha subunits decreased in response to UCP1 expression. Our results support the idea that the energy status of cells, and the ATP/ADP ratio in particular, modulates the lipolytic effects of noradrenaline in adipose tissue in vivo. They also demonstrate changes at the G-protein level that tend to overcome the reduction of lipolysis when ATP level in adipocytes is low. Therefore, respiratory uncoupling may exert a broad effect on hormonal signalling in adipocytes.

• MeSH
• adenosindifosfát metabolismus   MeSH
• adenosintrifosfát metabolismus   MeSH
• AMP cyklický metabolismus   MeSH
• DNA primery MeSH
• genotyp MeSH
• hepatocyty enzymologie   MeSH
• iontové kanály MeSH
• lipasa genetika   MeSH
• lipolýza * MeSH
• membránové proteiny genetika   fyziologie   MeSH
• mitochondriální proteiny MeSH
• myši inbrední C57BL MeSH
• myši transgenní MeSH
• myši MeSH
• noradrenalin metabolismus   MeSH
• proteiny vázající GTP metabolismus   MeSH
• regulace genové exprese enzymů MeSH
• sekvence nukleotidů MeSH
• transportní proteiny genetika   fyziologie   MeSH
• tuková tkáň enzymologie   metabolismus   MeSH
• uncoupling protein 1 MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• adenosindifosfát MeSH
• adenosintrifosfát MeSH
• AMP cyklický MeSH
• DNA primery MeSH
• iontové kanály MeSH
• lipasa MeSH
• membránové proteiny MeSH
• mitochondriální proteiny MeSH
• noradrenalin MeSH
• proteiny vázající GTP MeSH
• transportní proteiny MeSH
• Ucp1 protein, mouse MeSH Prohlížeč
• uncoupling protein 1 MeSH