N-Acetylcysteine Reduces Methemoglobin in an In-vitro Model of Glucose-6-phosphate Dehydrogenase Deficiency
Article first published online: 28 JUN 2008
Academic Emergency Medicine
Volume 5, Issue 3, pages 225–229, March 1998
How to Cite
Wright, R. O., Woolf, A. D., Shannon, M. W. and Magnani, B. (1998), N-Acetylcysteine Reduces Methemoglobin in an In-vitro Model of Glucose-6-phosphate Dehydrogenase Deficiency. Academic Emergency Medicine, 5: 225–229. doi: 10.1111/j.1553-2712.1998.tb02617.x
- Issue published online: 28 JUN 2008
- Article first published online: 28 JUN 2008
- Received: May 28, 1997; revision received: July 30, 1997; accepted: August 6, 1997; updated: November 2, 1997.
- glucose-6-phosphate dehydrogenase deficiency;
- G6PD deficiency;
Objective: To determine whether N-acetylcysteine (NAC) reduces methemoglobin (MHB) in an in-vitro model of glucose-6-phosphate dehydrogenase (G6PD) deficiency, given that methylene blue is an ineffective MHB antidote in G6PD deficiency.
Methods: Five volunteers donated blood, which was divided equally into 2 test tubes, centrifuged, and washed with Tris-Mopps buffer (pH 7.4, 15 mmol/L glucose). Both tubes were incubated with epiandrosterone (EA) (400 μmol), a specific inhibitor of G6PD. After 75 μL of 0.18 mol hydroxylamine (HA) was added to induce MHB formation, 150 μL of NAC (20 mg/mL) was added to tube 1 and 150 μL of phosphate-buffered saline (PBS) was added to tube 2 as a volume control. Serial MHB levels are reported as a percentage of total hemoglobin (Hb). G6PD activity was measured at baseline, 15 minutes after EA, and at 5 hours.
Results: Mean G6PD activity at baseline was 9.2 ± 2.9 U/g Hb (normal >4.6 U/g Hb); 15 minutes after EA was 3.0 ± 1.0 U/g Hb; and at experiment's end was 2.3 ± 0.7 U/g Hb. The mean (±SD) areas under the concentration-time curves (AUCs) of NAC-EA-HA and PBS-EA-HA samples were compared using an unpaired t-test and were significantly different: PBS-EA-HA, 20,400 ± 1,100 % min, vs NAC-EA-HA, 10,400 ± 1,000 % min, respectively (p < 0.05).
Conclusion: In this in-vitro model of G6PD deficiency, NAC efficiently reduced MHB.