Metabolic depression and Na+/K+ gradients in the aestivating Australian goldfields frog, Neobatrachus wilsmorei.
During aestivation the metabolic rate of the Australian goldfields frog Neobatrachus wilsmorei was reduced by 80% from its standard metabolic rate. The in vitro rate of oxygen consumption of isolated muscle and skin from aestivating frogs was up to 50% lower than that of the non-aestivating frogs. This in vitro rate of oxygen consumption was maintained for 6-12 h, indicating an intrinsic metabolic depression of tissues during aestivation. Frogs became dehydrated during aestivation. Muscle, skin and liver also became dehydrated during aestivation, but brain and kidney did not. Na+ and K+ contents and extracellular space measurement for muscle indicated that ion gradients were maintained across the muscle cell membrane during aestivation. Increases in plasma concentrations of Na+ and K+ were matched with similar increases in muscle intracellular ion concentrations. Extracellular space measurements were unsuccessful in the other tissues, but K+ content in all tissues (per dry weight) was maintained during aestivation, and the concentration of plasma K+ did not increase above that which can be accounted for by dehydration, indicating that K+ gradients were maintained.
Flanigan
J E
JE
Department of Biochemistry, University of Western Australia, Nedlands.
Withers
P C
PC
Fuery
C J
CJ
Guppy
M
M
D000818:Animals; D001001:Anura / Q000378:metabolism*; D001834:Body Water / Q000378:metabolism; D003681:Dehydration / Q000378:metabolism; D004956:Estivation / Q000502:physiology*; D005110:Extracellular Space / Q000378:metabolism; D006706:Homeostasis; D066298:In Vitro Techniques; D007424:Intracellular Fluid / Q000378:metabolism; D017136:Ion Transport; D010101:Oxygen Consumption; D011188:Potassium / Q000378:metabolism*; D012964:Sodium / Q000378:metabolism*; D014018:Tissue Distribution
D012964:Sodium; D011188:Potassium