Blockade of fatty acid oxidation mimics phase II-phase III transition in a fasting bird, the king penguin

• Main Authors: Servane F. Bernard, Eliane Mioskowski, Rene ́ Groscolas, Am J Physiol, Regulatory Integrative, Comp Physiol
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Published: 2002
• Subjects: King Penguins
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.1032.1137; http://ajpregu.physiology.org/content/ajpregu/283/1/R144.full.pdf

ajpregu.00011.2002.—This study tests the hypothesis that the metabolic and endocrine shift characterizing the phase II-phase III transition during prolonged fasting is related to a decrease in fatty acid (FA) oxidation. Changes in plasma concentrations of various metabolites and hormones and in lipolytic fluxes, as determined by continuous infusion of [2-3H]glycerol and [1-14C]palmitate, were examined in vivo in spontaneously fasting king penguins in the phase II status (large fat stores, protein sparing) before, during, and after treatment with mercaptoacetate (MA), an inhibitor of FA oxidation. MA induced a 7-fold decrease in plasma -hy-droxybutyrate and a 2- to 2.5-fold increase in plasma nones-terified fatty acids (NEFA), glycerol, and triacylglycerols. MA also stimulated lipolytic fluxes, increasing the rate of appear-ance of NEFA and glycerol by 60–90%. This stimulation