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Swelling-contraction of mitochondria in hypotonic medium

1966; Elsevier BV; Volume: 118; Issue: 3 Linguagem: Inglês

10.1016/s0926-6593(66)80088-7

1878-1454

Eva M. Suranyi, Y. Avi‐Dor,

Diet and metabolism studies

Swelling in a hypotonic medium is an energy-dependent process. The energy can be derived either from respiration or from ATP. In the presence of ATP, the time-course of volume changes revealed three distinct phases: lag, swelling, and spontaneous recontraction. The onset of swelling was delayed in the presence of K+. Higher concentrations of ATP were required to induce recontraction than to extend the lag time. Neither the onset of swelling nor that of recontraction was connected with a change in the rate of hydrolysis of ATP. 2,4-Dinitrophenol shortened the lag and increased the rate and the extent of the swelling and of recontraction. Oligomycin and atractyloside each abolished all the observed effects of ATP on swelling. In the absence of ATP, uncouplers of oxidative phosphorylation and respiratory inhibitors inhibited swelling, but the inhibition could be overcome by ATP. The significance of these findings is discussed in the light of some recent hypotheses on the interrelation between electron transport, energy transfer and volume changes.