Changes in angiotensin converting enzyme activity in the renal vascular bed of streptozotocin-induced diabetic rat.
The purpose of this study was to look for evidence of changes in angiotensin converting enzyme activity in the renal vascular bed of streptozotocin (STZ)-induced diabetic rats. To assess the activity of the enzyme, we examined angiotensin I- and angiotensin II-induced vasoconstriction in perfused kidneys from controls and diabetic rats. Angiotensin I (3x10(-9) to 3x10(-6) M) induced a dose-dependent vasoconstriction in control kidneys; this response was completely inhibited by losartan (10(-5) M) and markedly inhibited by both captopril (10(-4) M) and indomethacin (10(-5) M). Angiotensin II (10(-10) to 3x10(-7) M) also caused a dose-dependent vasoconstriction in control kidneys; this response was markedly enhanced by 10(-4) M L-NNA, and significantly inhibited by losartan (10(-5) M). Angiotensin I-induced vasoconstriction was slightly greater in STZ-induced diabetic rats than in controls, but the maximal response was unaffected. These results suggest that angiotensin I is rapidly converted to angiotensin II in the renal vascular bed, and that converting enzyme activity in the renal vascular bed may be decreased in STZ-induced diabetic rats.
Kamata
K
K
Department of Physiology and Morphology, Institute of Medicinal Chemistry Hoshi University, Tokyo, Japan. kamata@hoshi.ac.jp
Mizutani
K
K
D000803:Angiotensin I / Q000037:antagonists & inhibitors / Q000378:metabolism / Q000494:pharmacology*; D000804:Angiotensin II / Q000494:pharmacology*; D057911:Angiotensin Receptor Antagonists; D000818:Animals; D000959:Antihypertensive Agents / Q000494:pharmacology; D001786:Blood Glucose; D002216:Captopril / Q000494:pharmacology; D003921:Diabetes Mellitus, Experimental / Q000378:metabolism*; D004347:Drug Interactions; D007668:Kidney / Q000187:drug effects* / Q000201:enzymology / Q000378:metabolism; D019808:Losartan / Q000494:pharmacology; D008297:Male; D009131:Muscle, Smooth, Vascular / Q000187:drug effects* / Q000378:metabolism; D007703:Peptidyl-Dipeptidase A / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D012077:Renal Artery / Q000187:drug effects* / Q000378:metabolism; D013311:Streptozocin; D014661:Vasoconstriction / Q000187:drug effects
D057911:Angiotensin Receptor Antagonists; D000959:Antihypertensive Agents; D001786:Blood Glucose; D000804:Angiotensin II; D013311:Streptozocin; D000803:Angiotensin I; D002216:Captopril; D007703:Peptidyl-Dipeptidase A; D019808:Losartan