Regulation of Metabolism in Working Muscle in Vivo

Abstract

Abstract The concentrations of adenosine mono-, di-, and triphosphates, arginine phosphate, and inorganic phosphate in flight muscle of the blowfly, Phormia regina, were measured concurrently after periods of flight ranging from 5 sec to 1 hour. At the onset of contraction, the concentrations of ATP and arginine-P decreased, whereas those of ADP, Pi, and especially AMP, increased. The pattern of changes in these phosphates is in accord with the postulated mechanism of glycolytic regulation at the phosphofructokinase step. Possible oscillatory responses induced by the initiation of active contraction in vivo are suggested.