EFFECTS OF HYPOXIA AND TOXICANT EXPOSURE ON PHOSPHOARGININE, INTRACELLULAR PH, AND FREE MG2-31-NMR( IN ABALONE AS MEASURED BY P)

The effects of hypoxia, sodium azide and pentachlorophenol (PCP) expos ure on high-energy phosphorylated compounds, intracellular pH (PHi) an d intracellular free Mg2+ (Mg-f) in intact red abalone (Haliotis rufes cens) were determined using P-31-NMR. Abalone made hypoxic by bubbling sea water with N-2 showed modest changes in phosphoarginine (PA) and inorganic phosphate (P-i) concentrations, no significant changes in pH (i) and a moderate decrease in Mg-f that was not statistically signifi cant. Azide (50 mg/l) exposed animals displayed severe declines in PA dropping to 0.53 of reference values, coupled with large increases in P-i to 10.66 times resting concentrations that occurred just after the 2-hr exposure period. pH(i) also showed significant declines from a r esting value of 7.17-7.06 (P < 0.05) but fully recovered by the end of the 6-hr clean seawater recovery period, whereas Mg-f concentrations declined slightly during the exposure period but increased by 18% at t he end of the recovery period relative to reference Mg-f. PCP (1.2 mg/ l) exposed animals displayed similar increases and declines in P-i and PA, respectively, as did azide-exposed animals by the end of the expo sure period, but recovery was much slower and occurred in a bimodal fa shion with some animals completely recovering at the end of 6 hr and o thers essentially stabilized at the end of the exposure period and did not show any significant changes during the recovery period. (C) 1997 Elsevier Science Inc.