Reduced cortical renal GLUT1 expression induced by angiotensin-converting enzyme inhibition in diabetic spontaneously hypertensive rats
Braz. j. med. biol. res
;
41(11): 960-968, Nov. 2008. graf, tab
Artículo
en Inglés
| LILACS
| ID: lil-500363
ABSTRACT
Diabetes in spontaneously hypertensive rats is associated with cortical renal GLUT1 and GLUT2 overexpression. Our objective was to evaluate the effect of the angiotensin-converting enzyme blockade on cortical renal GLUT1 and GLUT2 expression, urinary albumin and urinary TGF-¦Â1. Streptozotocin, 50 mg/kg, or citrate buffer (N = 16) was administered as a single injection into the tail vein in adult spontaneously hypertensive rats (~260 g). Thirty days later, these diabetic spontaneously hypertensive rats received ramipril by gavage 0.01 mg¡¤kg-1¡¤day-1 (D0.01, N = 14), 1 mg¡¤kg-1¡¤day-1 (D1, N = 9) or water (D, N = 11) for 15 days. Albumin and TGF-¦Â1 (24-h urine), direct arterial pressure, renal tissue angiotensin-converting enzyme activity (fluorometric assay), and GLUT1 and GLUT2 protein levels (Western blot, renal cortex) were determined. Glycemia and glycosuria were higher (P < 0.05) in the diabetic rats compared with controls, but similar between the diabetic groups. Diabetes in spontaneously hypertensive rats lowered renal tissue angiotensin-converting enzyme activity (40 percent), which was reduced further when higher ramipril doses were used. Diabetes associated with hypertension raised GLUT1 by 28 percent (P < 0.0001) and GLUT2 by 76 percent (P = 0.01), and both doses of ramipril equally reduced cortical GLUT1 (D vs D1 and vs D0.01, P ¡Ü 0.001). GLUT2 levels were reduced in D0.01 (P < 0.05 vs D). Diabetes increased urinary albumin and TGF-¦Â1 urinary excretion, but the 15-day ramipril treatment (with either dose) did not reduce them. In conclusion, ramipril is effective in lowering renal tissue angiotensin-converting enzyme activity, as well as blocking cortical GLUT1 overexpression, which may be beneficial in arresting the development of diabetic nephropathy.
Texto completo:
Disponible
Índice:
LILACS (Américas)
Asunto principal:
Inhibidores de la Enzima Convertidora de Angiotensina
/
Ramipril
/
Transportador de Glucosa de Tipo 1
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Corteza Renal
Límite:
Animales
Idioma:
Inglés
Revista:
Braz. j. med. biol. res
Asunto de la revista:
Biologia
/
Medicina
Año:
2008
Tipo del documento:
Artículo
País de afiliación:
Brasil
Institución/País de afiliación:
Fundação Universit¨¢ria de Cardiologia/BR
/
Universidade Federal do Rio Grande do Sul/BR
/
Universidade de São Paulo/BR
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