Acute diabetes mellitus and its influence on renal Na,K-ATPase in both genders.

Due to the importance of renal Na,K-ATPase in maintaining the sodium homeostasis in the organism, its activity and abundance is intensively studied in condition of diabetes mellitus. The main subject of this study was the investigation of properties of renal Na,K-ATPase and abundance of its alpha1 subunit in view of possible gender-dependent differences in male and female diabetic rats. Diabetes was induced by a single intraperitoneal dose of streptozotocin in a dose of 65 mg.kg(-1). The acute diabetes lasting 8 days induced a significant increase in Na,K-ATPase activity accompanied by significant gender specific increase in K(m) value indicating a worsened affinity of ATP-binding site in female rats. In addition, our present experiments, revealed a significantly higher abundance of renal Na,K-ATPase alpha1 subunit in diabetic rats of both genders amounting 94% increase in males and 107% in females. But, not all of the newly synthesized enzyme molecules are fully active, as the increase in the number of active molecules is smaller (representing 23% in males and 20% in females) as indicated by lower increase in V(max) values.