Sodium potassium ATPase and glucose 6 phosphate dehydrogenase activity in patients with hyperthyroidism: a comparison with euthyroid patients

ABSTRACT

Sodium potassium ATPase [Na+-K+ ATPase] and Glucose 6 phosphate dehydrogenase [G 6 PD] activities in different tissues have been found to be stimulated by thyroid hormones. In erythrocytes, the activities of these enzymes were reported to vary. The aim of our study was to determine the sodium potassium ATPase and glucose 6 phosphate dehydrogenase activities in patients with hyperthyroidism and compare them with those of patients with euthyroid goiter. After approval from the Institutional Ethics Committee and obtaining informed consent from all patients, 40 hyperthyroid patients [17 men, 23 women; mean age 44.75 +/- 2.6 years] and 50 patients with euthyroid goiter [13 men, 37 women; mean age 37.2 +/- 1.6 years] were included in the study. They were classified based on T3, T4, TSH measurements. Erythrocyte Na+-K+ ATPase and G 6 PD activity were measured using spectrophotometry. In hyperthyroid patients, Na+-K+ ATPase activity was significantly lower compared to euthyroid controls [134.98 +/- 3.78 vs. 164.34 +/- 3.85 nmol pi/hr.mg protein, p<0.001] and G 6 PD levels were significantly elevated when compared to euthyroid controls [19.19 +/- 0.438 U/g Hb vs. 11.505 +/- 0.385 U/g Hb, p<0.001]. Hyperthyroidism is associated with decrease in Na+-K+ ATPase activity and increase in G 6 PD levels when compared to patients with euthyroid goiter. The measurement of Na+-K+ATPase activity could be used as an early marker for diagnosis of hyperthyroidism