Effects of taurine and enalapril on kidney function of the hypertensive glucose-intolerant rat.
BACKGROUND
Recent studies indicate that the coexistence of hypertension and glucose intolerance leads to impairment in saline volume-induced diuresis and natriuresis. Furthermore, taurine and enalapril affect renal function and blood pressure (BP). Therefore, we tested the hypothesis that therapy combining taurine and enalapril would confer greater antihypertensive activity and responsiveness to saline volume loading in the hypertensive glucose-intolerant (HGI) rat than either agent alone.


METHODS
Hypertensive (H) and HGI rats were treated from 6 weeks to 6 months with tap water containing no addition, taurine (0.25%), enalapril (15 mg/kg/day), or the taurine-enalapril combination. Hemodynamic and renal responses to an intravenous isotonic saline volume load were then determined in the conscious animal.


RESULTS
The vehicle-treated HGI rats displayed reduced saline volume-induced diuresis and natriuresis relative to their H counterparts. Although none of the three drug regimens affected BP, they were similarly effective in increasing the renal excretory responses to saline volume loading and in eliminating differences that existed between the untreated H and HGI groups. Although reduced tubular reabsorption activity contributed to the taurine- and enalapril-mediated augmentation in renal excretory function, enalapril also enhanced glomerular function. The augmentation in the glomerular filtration rate was greatest in the HGI rat treated with the combination of taurine and enalapril. Furthermore, all three drug regimens significantly reduced protein excretion in both H and HGI rats.


CONCLUSIONS
Despite exerting no influence on BP, all three drug regimens were renoprotective, as indicated by the drug-mediated improvement in kidney function of the HGI rat.
Mozaffari
Mahmood S
MS
Department of Oral Biology and Maxillofacial Pathology, CB 3710, Medical College of Georgia School of Dentistry, Augusta, GA 30912-1128, USA. mmozaffa@mail.mcg.edu
Miyata
Noriyuki
N
Schaffer
Stephen W
SW
D000806:Angiotensin-Converting Enzyme Inhibitors / Q000494:pharmacology*; D000818:Animals; D000831:Animals, Newborn; D000959:Antihypertensive Agents / Q000494:pharmacology*; D001835:Body Weight / Q000187:drug effects; D003921:Diabetes Mellitus, Experimental / Q000150:complications / Q000503:physiopathology; D004656:Enalapril / Q000494:pharmacology*; D005919:Glomerular Filtration Rate / Q000187:drug effects; D018149:Glucose Intolerance / Q000503:physiopathology*; D005951:Glucose Tolerance Test; D006439:Hemodynamics / Q000502:physiology; D006973:Hypertension / Q000188:drug therapy / Q000503:physiopathology*; D006977:Hypertension, Renal / Q000503:physiopathology; D007668:Kidney / Q000187:drug effects / Q000502:physiology*; D007677:Kidney Function Tests; D008297:Male; D009929:Organ Size / Q000187:drug effects; D051381:Rats; D011921:Rats, Inbred WKY; D012964:Sodium / Q000652:urine; D013654:Taurine / Q000494:pharmacology*
D000806:Angiotensin-Converting Enzyme Inhibitors; D000959:Antihypertensive Agents; D013654:Taurine; D004656:Enalapril; D012964:Sodium