title: The thermodynamic degree of coupling between metabolism and sodium transport in frog skin.
abstract: The tightness of coupling between two processes is advantageously evaluated by the thermodynamic degree of coupling q, varying in absolute value from zero for uncoupled processes to unity for processes which are related stoichiometrically. Two methods for the determination of q in the active pathway in frog skin have been developed, employing amiloride to abolish active sodium transport. The values of q in 6 frog skins varied, but were always less than unity (mean 0.79 +/- 0.06 S.E. according to one method, 0.78 +/- 0.06 S.E. according to the other). This indicates that metabolism and sodium transport are incompletely coupled in this tissue even when passive transepithelial leakage pathways are taken into account.
mesh_terms: D000584:Amiloride / Q000494:pharmacology; D001693:Biological Transport, Active; D008564:Membrane Potentials; D010101:Oxygen Consumption; D012867:Skin / Q000378:metabolism*; D012964:Sodium / Q000378:metabolism*; D013816:Thermodynamics
chemical_list: D000584:Amiloride; D012964:Sodium