Metabolic control of intracellular ion concentrations in the frog skin epithelium.
The effects of the metabolic inhibitors 2-deoxy-d-glucose and monofluoroacetate on intracellular ion concentrations and Na transport rate were investigated in the isolated frog skin epithelium of Rana pipiens. Ion concentrations were determined in thin freeze-dried cryosections using energy-dispersive X-ray microanalysis. Metabolic inhibition was compared to direct inhibition of the Na pump by ouabain. At similar rates of transepithelial Na transport, inhibition of the Na pump always resulted in much more pronounced Na concentration increase than metabolic inhibition. This result suggests that the apical Na influx is under effective metabolic control. Downregulation of the Na influx during impaired cellular energy metabolism may be a means by which transporting epithelial cells avoid potentially damaging derangements of the intracellular ion composition.
Rick
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Department of Physiology and Biophysics, University of Alabama, Birmingham.
D000818:Animals; D001693:Biological Transport, Active; D003847:Deoxyglucose / Q000494:pharmacology; D004553:Electric Conductivity; D004573:Electrolytes / Q000378:metabolism; D004577:Electron Probe Microanalysis; D004848:Epithelium / Q000187:drug effects / Q000378:metabolism; D005463:Fluoroacetates / Q000494:pharmacology; D066298:In Vitro Techniques; D009994:Osmolar Concentration; D010042:Ouabain / Q000494:pharmacology; D011894:Rana pipiens; D012867:Skin / Q000187:drug effects / Q000378:metabolism*; D012964:Sodium / Q000037:antagonists & inhibitors / Q000378:metabolism*; D015222:Sodium Channels / Q000378:metabolism
D004573:Electrolytes; D005463:Fluoroacetates; D015222:Sodium Channels; D010042:Ouabain; D003847:Deoxyglucose; D012964:Sodium; C014815:fluoroacetic acid