title: Characteristics of 45Ca uptake and efflux in rat lung slices.
abstract: The distribution and movements of 45Ca were investigated in lung slice preparations obtained from rats. The accumulation of 45Ca was measured in either 5.0 mM Ca2+, 0.5 mM Ca2+ or 0-Ca solutions. The 45Ca tissue to medium ratio was greatest in the 0-Ca solution; the presence of either 5.0 mM Ca2+ or 0.5 mM Ca2+ reduced this ratio 8- and 5-fold, respectively. Efflux of 45Ca indicated that there are at least two washout components. Exposure to either La3+ or Sr2+ (0.5 mM) during the washout resulted in a transient increase in 45Ca efflux (Sr2+ greater than La3+), whereas 0 degrees C slowed the loss of 45Ca. Uptake of 45Ca was increased by the metabolic inhibitor iodoacetic acid and inhibited in the presence of either La3+ or Sr2+. These findings indicate that the 45Ca accumulated within the lung is not readily depleted and a portion appears to accumulate at intracellular or less superficial sites or stores.
mesh_terms: D000818:Animals; D002118:Calcium / Q000378:metabolism*; D066298:In Vitro Techniques; D007461:Iodoacetates / Q000494:pharmacology; D007811:Lanthanum / Q000494:pharmacology; D008168:Lung / Q000187:drug effects / Q000378:metabolism*; D008297:Male; D009994:Osmolar Concentration; D051381:Rats; D013324:Strontium / Q000494:pharmacology; D013696:Temperature; D013997:Time Factors
chemical_list: D007461:Iodoacetates; D007811:Lanthanum; D002118:Calcium; D013324:Strontium