Diuretic Action of Exogenous Hydrogen Sulfide in Spontaneously Hypertensive Diabetic Rats

Purpose: To examine the hypothesis that in hypertensive diabetic rats hydrogen sulphide (H₂S) reduces blood pressure through diuretic action in addition to its vasodilating effect.
Methods: Spontaneously hypertensive rats (SHR) and Wistar-Kyoto (WKY) rats were used. SHR were divided into three groups: SHR (II), SHR diabetic (III), and SHR diabetic NaHS-Treated (IV) with a group of WKY (I) rats serving as normotensive nondiabetic control. Diabetes was produced in two SHR groups using intraperitoneal streptozotocin (STZ). One diabetic group received NaHS, a donor of H₂S (56 μM/kg i.p.) daily for five weeks. Blood pressure was measured in conscious and anesthetized states in surgically prepared animals. Plasma and urinary H₂S levels and electrolytes were measured weekly throughout the 35-day period.
Results: SHR and diabetic SHR had higher blood pressure and lower plasma and urinary H₂S levels compared to WKY controls (p < 0.05). Moreover, the SHR diabetic group had higher plasma sodium, higher absolute and fractional sodium excretions (p < 0.05) but with similar blood pressure compared to SHR controls. NaHS treatment reduced blood pressure and restored H₂S and plasma sodium (p < 0.05) levels. Moreover, SHR diabetic-NaHS treated group had higher urine output and absolute urinary sodium excretion compared to the untreated SHR diabetic group (p < 0.05).
Conclusion: These results suggest a possible diuretic effect of exogenous H₂S in spontaneously hypertensive diabetic rats.

Keywords
Spontaneously hypertensive rats; Diabetes; Hydrogen sulphide; Diuretic; Sodium excretion; Urine output