Effects of hypoxia and toxicant exposure on phosphoarginine, intracellular pH, and free Mg2+ in abalone as measured by 31P-NMR

The effects of hypoxia, sodium azide and pentachlorophenol (PCP) exposure on high-energy phosphorylated compounds, intracellular pH (pH(i)) and intracellular free Mg²⁺ (Mg(f)) in intact red abalone (Haliotis rufescens) were determined using ³¹P-NMR. Abalone made hypoxic by bubbling sea water with N2 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 significant. 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 resting 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 the 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 exposure period, but recovery was much slower and occurred in a bimodal fashion with some animals completely recovering at the end of 6 hr and others essentially stabilized at the end of the exposure period and did not show any significant changes during the recovery period.

Duke Scholars

Author Scott Leigh Shofer Medicine, Pulmonary, Allergy, and Critical Care Medicine