Glycolytic enzyme binding during entrance to daily torpor in deer mice (Peromyscus maniculatus).
Associations of glycolytic enzymes with the subcellular particulate fraction of skeletal muscle and heart were examined during entrance to daily torpor in deer mice (Peromyscus maniculatus). In skeletal muscle a significant decrease in enzyme binding occurred during torpor entrance for phosphofructokinase, glyceraldehyde-3-phosphate dehydrogenase, and pyruvate kinase, with an additional significant decrease for phosphofructokinase and pyruvate kinase during the deepest state of torpor. Reductions in enzyme binding during torpor entrance also occurred in heart; significant changes were observed in hexokinase, glyceraldehyde-3-phosphate dehydrogenase, and pyruvate kinase binding. Contrary to the finding of additional reductions in enzyme binding seen in skeletal muscle, significant increases in enzyme binding during the deepest torpor state were observed for hexokinase, phosphofructokinase, glyceraldehyde-3-phosphate dehydrogenase, pyruvate kinase, and lactate dehydrogenase in heart. These results suggest that a decrease in the binding of glycolytic enzymes to subcellular structures in skeletal muscle and heart may be at least partially responsible for initiating the reduction in metabolic rate during torpor entrance. This decreased binding may continue to mediate the metabolic reduction in skeletal muscle throughout torpor; heart, however, may require the use of different molecular mechanisms. The increased binding in heart during the deepest state of torpor may represent an anticipatory response in preparation for increased activity during arousal.
Nestler
J R
JR
Department of Biological Sciences, Walla Walla College, Washington 99324, USA.
Peterson
S J
SJ
Smith
B D
BD
Heathcock
R B
RB
Johanson
C R
CR
Sarthou
J C
JC
King
J C
JC
D000704:Analysis of Variance; D000818:Animals; D001831:Body Temperature / Q000502:physiology; D002940:Circadian Rhythm / Q000502:physiology*; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases / Q000032:analysis / Q000378:metabolism* / Q000502:physiology; D006003:Glycogen / Q000378:metabolism; D006321:Heart / Q000502:physiology; D006593:Hexokinase / Q000032:analysis / Q000378:metabolism / Q000502:physiology; D006605:Hibernation / Q000502:physiology; D007770:L-Lactate Dehydrogenase / Q000032:analysis / Q000378:metabolism / Q000502:physiology; D051379:Mice; D018482:Muscle, Skeletal / Q000166:cytology / Q000201:enzymology* / Q000502:physiology; D009206:Myocardium / Q000166:cytology / Q000201:enzymology; D010542:Peromyscus / Q000378:metabolism / Q000502:physiology*; D010732:Phosphofructokinase-1 / Q000032:analysis / Q000378:metabolism* / Q000502:physiology; D011770:Pyruvate Kinase / Q000032:analysis / Q000378:metabolism* / Q000502:physiology
D006003:Glycogen; D007770:L-Lactate Dehydrogenase; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases; D006593:Hexokinase; D010732:Phosphofructokinase-1; D011770:Pyruvate Kinase