HYDROGEN-PEROXIDE CAUSES A DECREASE IN AEROBIC METABOLIC-RATE AND IN INTRACELLULAR PH IN THE SHRIMP CRANGON-CRANGON

UV-dependent hydrogen peroxide formation can lead to high levels of hy drogen peroxide in tidepool waters. The effect of ambient hydrogen per oxide on the rate of oxygen consumption and on the levels of intracell ular pH, lactate and high energy phosphates was studied in the shrimp, Crangon crangon. Exposure to elevated hydrogen peroxide levels caused a decrease in metabolic rate by an average value of 26% in intact ani mals and by up to 60% in isolated preparations of the tail muscle. Mus cle intracellular pH decreased by 0.1-0.2 pH units in both isolated ti ssue and intact animal. The maintenance of lactate and ATP at control levels strongly suggests that the acidosis was not associated with ana erobic proton production and, as a corollary, must be explained throug h an effect of hydrogen peroxide on proton equivalent ion exchange mec hanisms. Future studies will attempt to elucidate the nature of the ef fect and whether the associated acidosis leads to the observed decreas e in aerobic metabolic rate. (C) 1997 Elsevier Science Inc.