Induction of functional uncoupling protein in guinea pigs infused with noradrenaline. Studies with isolated brown adipocytes.
Continuous infusion of noradrenaline over the interscapular brown fat of guinea pigs maintained at thermoneutrality (28-32 degrees C) induces changes similar to those after cold-adaptation. (1) Multilocular fat droplets appear within the brown adipocytes. (2) The number of mitochondria per adipocyte and the total number of adipocytes both increase. (3) Noradrenaline addition to isolated adipocytes causes near maximal uncontrolled respiration. (4) The cells become more sensitive to fatty acid-induced uncoupling. (5) The tissue-specific uncoupling protein per mg of mitochondrial protein is increased 5-fold. Specific alpha- and beta-agonists were also chronically infused. (6) Separate infusion of phenylephrine or isoprenaline was not able to stimulate mitochondriogenesis or hyperplasia. (7) Adipocytes from these animals could not be uncoupled by acute noradrenaline. (8) Simultaneous chronic infusion of phenylephrine and isoprenaline reproduced the effects of chronic noradrenaline infusion.
Cunningham
S A
SA
Department of Biochemistry, University of Dundee, Scotland, U.K.
Nicholls
D G
DG
D002001:Adipose Tissue, Brown / Q000187:drug effects / Q000378:metabolism*; D000818:Animals; D002259:Carbonyl Cyanide p-Trifluoromethoxyphenylhydrazone / Q000494:pharmacology; D002352:Carrier Proteins; D003080:Cold Temperature; D006153:Guanosine Diphosphate / Q000378:metabolism; D006168:Guinea Pigs; D066298:In Vitro Techniques; D007473:Ion Channels; D007700:Kinetics; D008565:Membrane Proteins / Q000378:metabolism*; D008928:Mitochondria / Q000378:metabolism; D024101:Mitochondrial Proteins; D009638:Norepinephrine / Q000494:pharmacology*; D010101:Oxygen Consumption / Q000187:drug effects; D019308:Palmitic Acid; D010169:Palmitic Acids / Q000494:pharmacology; D014475:Uncoupling Agents / Q000378:metabolism*; D000071256:Uncoupling Protein 1
D002352:Carrier Proteins; D007473:Ion Channels; D008565:Membrane Proteins; D024101:Mitochondrial Proteins; D010169:Palmitic Acids; D014475:Uncoupling Agents; D000071256:Uncoupling Protein 1; D006153:Guanosine Diphosphate; D019308:Palmitic Acid; D002259:Carbonyl Cyanide p-Trifluoromethoxyphenylhydrazone; D009638:Norepinephrine