The Effect of Hydrochlorothiazide and Triamterene on the Tissue Content of Sodium and Potassium in the Rat 1

Summary

Hydrochlorothiazide (HCTZ), triamterene (TA), HCTZ plus TA or saline was administered orally to female albino rats once daily for 7 days. Plasma, kidney, heart, and skeletal muscle (biceps femoris) were analyzed for Na⁺, K⁺, and water content. Skeletal muscle was found to be the most sensitive, of the tissues examined, to alteration in ionic content following the administration of these diuretic agents. The Na⁺ content of skeletal muscle was significantly increased with HCTZ and was significantly decreased following TA alone or TA plus HCTZ. The increase observed following HCTZ was unexpected in view of the natriuretic action of this agent. Treatment with TA alone caused a significant depression of Na⁺ content of the heart. A significant decrease in K⁺ was observed in skeletal muscle following TA plus HCTZ and an increase in kidney following TA alone. It is apparent from this study that HCTZ and TA can affect the tissue content of Na⁺ and/or K⁺ without an apparent effect on plasma levels of these ions. A possible interaction of these diuretics with aldosterone to produce these ionic changes is discussed.