Increased in vitro fatty acid supply and cellular transport capacities in cold-acclimated ducklings (Cairina moschata).
In cold-acclimated (CA) birds, lipids play a crucial role in regulatory thermogenesis by acting both as substrates for and activators of thermogenic processes. The capacity to supply lipids to thermogenic tissues, which could limit cold thermogenesis, was assessed in CA ducklings (5 wk old, 4 degrees C) and compared with thermoneutral controls (TN, 25 degrees C). In CA ducklings, basal lipolytic activity of adipose tissue fragments was higher (202 +/- 9 vs. 130 +/- 14 nmol glycerol released . 100 mg tissue-1 . h-1, +55%) than in TN controls, while glucagon had a much higher stimulatory effect (+140 to +500% depending on dose). This was consistent with increased plasma levels of nonesterified fatty acids (FA, +57%) and glycerol (+31%) in vivo. In vitro endothelial lipase activity per organ was higher in CA than in TN ducklings in red gastrocnemius muscle (6.3 +/- 0.6 vs. 3.5 +/- 0.3 microeq nonesterified FA released per hour, +80%) and liver (+55%). The intracellular FA-binding capacity of (12-18 kDa) proteins was higher in gastrocnemius muscle (+43%) and liver (+74%) from CA ducklings. In gastrocnemius, it was linked to a higher content (21 +/- 2 vs. 15 +/- 2 microg/mg protein, +37%) of an intracellular 15.4-kDa FA-binding protein. These in vitro results indicate that coordinated increases in FA supply from adipose tissue, cellular uptake of lipoprotein-derived FA, and intracellular FA transport capacity occur in CA ducklings endowed with higher thermogenic capacity and cold endurance.
Bénistant
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Unité Mixte de Recherches 5578 Centre National de la Recherche Scientifique-Université Claude Bernard Lyon I, Laboratoire Associé Institut National de la Recherche Agronomique, Villeurbanne, France.
Duchamp
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Cohen-Adad
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F
Rouanet
J L
JL
Barré
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H
D000064:Acclimatization; D000273:Adipose Tissue / Q000378:metabolism; D000818:Animals; D001692:Biological Transport; D001833:Body Temperature Regulation; D002352:Carrier Proteins / Q000032:analysis / Q000302:isolation & purification; D003080:Cold Temperature; D004372:Ducks / Q000378:metabolism*; D004730:Endothelium, Vascular / Q000201:enzymology; D050556:Fatty Acid-Binding Proteins; D005227:Fatty Acids / Q000378:metabolism*; D005230:Fatty Acids, Nonesterified / Q000097:blood; D005934:Glucagon / Q000494:pharmacology; D005990:Glycerol / Q000097:blood / Q000378:metabolism; D008049:Lipase / Q000378:metabolism; D008055:Lipids / Q000097:blood; D008066:Lipolysis; D008099:Liver / Q000201:enzymology; D008297:Male; D018482:Muscle, Skeletal / Q000737:chemistry / Q000201:enzymology; D018996:Myelin P2 Protein / Q000032:analysis / Q000302:isolation & purification; D009363:Neoplasm Proteins
D002352:Carrier Proteins; D050556:Fatty Acid-Binding Proteins; D005227:Fatty Acids; D005230:Fatty Acids, Nonesterified; D008055:Lipids; D018996:Myelin P2 Protein; D009363:Neoplasm Proteins; D005934:Glucagon; D008049:Lipase; D005990:Glycerol