Increased proximal tubule NHE-3 and H+-ATPase activities in spontaneously hypertensive rats.

Abstract

OBJECTIVE:

To investigate renal proximal tubular sodium-hydrogen exchanger 3 (NHE-3) and H+-ATPase activities in young (5-week-old) spontaneously hypertensive rats (SHR) and normotensive Donryu (DRY) rats, in the period during which high blood pressure is developing.

METHODS:

Five-week-old SHR and DRY rats were weighed and systolic blood pressure recorded. Proximal tubule cells were isolated, loaded with the intracellular pH dye, 2'-7'-bis-carboxyethyl-5(6)-carboxyfluorescein-acetoxymethyl-ester and acidified with a NH4+/NH3 prepulse. Na+-independent intracellular pH recovery rate (H+-ATPase activity) and initial Na+-dependent intracellular pH recovery rate (NHE-3 activity) were assessed. NHE-3 activity was assessed during inhibition of H+-ATPase with Bafilomycin A1 and during inhibition of any possible NHE-1 activity with Hoe 694.

RESULTS:

Mean body weight and systolic blood pressures of 5-week-old SHR and DRY rats were not significantly different. NHE-3 activity was higher in SHR, 1.08 +/- 0.1 pH units/min compared with DRY rats, 0.73 +/- 0.1 pH units/min (P < 0.05) H+-ATPase activity was also higher in SHR, 0.119 +/- 0.02 pH units/min, compared with DRY rats, 0.051 +/- 0.02 pH units/min (P < 0.05).

CONCLUSIONS:

Proximal tubule cells of 5-week-old SHR have higher NHE-3 and H+-ATPase activities compared with age-matched DRY rats. Enhanced proximal tubular fluid reabsorption is likely to contribute to development of high blood pressure in young SHR.

• Authors: K L Aldred, P J Harris, E Eitle
• Journal: Journal of hypertension (J Hypertens) Vol. 18 Issue 5 Pg. 623-8 (May 2000) ISSN: 0263-6352 [Print] England
• PMID: 10826566 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Anti-Bacterial Agents
• Enzyme Inhibitors
• Guanidines
• Macrolides
• Slc9a3 protein, rat
• Sodium-Hydrogen Exchanger 3
• Sodium-Hydrogen Exchangers
• Sulfones
• 3-methylsulfonyl-4-piperidinobenzoyl guanidine
• bafilomycin A1
• Proton-Translocating ATPases

Topics

• Animals
• Anti-Bacterial Agents (pharmacology)
• Blood Pressure
• Enzyme Inhibitors (pharmacology)
• Guanidines (pharmacology)
• Hydrogen-Ion Concentration
• Hypertension (etiology, metabolism, physiopathology)
• In Vitro Techniques
• Intracellular Fluid (metabolism)
• Kidney Tubules, Proximal (drug effects, metabolism)
• Macrolides
• Male
• Proton-Translocating ATPases (antagonists & inhibitors, metabolism)
• Rats
• Rats, Inbred SHR
• Sodium-Hydrogen Exchanger 3
• Sodium-Hydrogen Exchangers (antagonists & inhibitors, metabolism)
• Sulfones (pharmacology)