Temperature Effects on Phosphate Uptake and Release in the Isolated Rabbit Heart

¹ From the Department of Physiology, Stritch School of Medicine, Loyola University, Chicago, Illinois

Radiophosphate uptake by the isolated rabbit heart fails to increase with temperature when the organ is perfused for 1 hour with Ringer-Locke's solution containing 5 µg P/ml. The low perfusate oxygen and phosphate concentrations appear to be partly responsible for this result. Phosphate concentration in the effluent perfusate increases with temperature. Thus, phosphate release does not appear to be immediately dependent upon entrance of phosphate. The lower total acid-soluble phosphate content at 37° compared to 26° is accounted for largely by differences in phosphocreatine and adenosine polyphosphate concentrations. The underlying basis for cellular release of phosphate may therefore be related to degradation of high energy phosphate.

Note:
with the technical assistance of Mitsuko Eto