Erythrocyte membrane calcium adenosine 5'-triphosphatase activity in the spontaneously hypertensive rat

• Published in: Clinical science (1979) Vol. 77; no. 4; pp. 395 - 400
• Main Authors: ADEOYA, A. S, NORMAN, R. I, BING, R. F
• Format: Journal Article
• Language: English
• Published: London Portland Press 01.10.1989
• Subjects: Animals; Arterial hypertension. Arterial hypotension; Biological and medical sciences; Blood and lymphatic vessels; Calcium - metabolism; Calcium-Transporting ATPases - metabolism; Calmodulin - metabolism; Cardiology. Vascular system; Erythrocyte Membrane - enzymology; Experimental diseases; Female; Hypertension - enzymology; Medical sciences; Rats; Rats, Inbred SHR; Rats, Inbred WKY; Hypertension; Pathophysiology; Rat; Enzyme; Rodentia; Ca,Mg-ATPase; Red blood cell; Cardiovascular disease; Hereditary; Vertebrata; Experimental disease; Mammalia; Animal; Plasma membrane
• ISSN: 0143-5221; 1470-8736
• DOI: 10.1042/cs0770395

1. Ca2+-adenosine 5'-triphosphatase (Ca2+-Mg2+-ATPase) activity was studied simultaneously in calmodulin-deficient erythrocyte ghost membranes and inside-out vesicles (IOVs) from 12-week-old female spontaneously hypertensive rats (SHR) and their matched controls: [Wistar-Kyoto normotensive rats (WKY)], and in detergent extracts of ghost membranes. 2. Both adenosine 5'-triphosphate (ATP)-dependent Ca2+ uptake by IOVs and Ca2+-dependent ATP hydrolysis activity of ghost membranes were reduced significantly in the SHR compared with WKY, when either the calmodulin-independent or calmodulin-stimulated activities were compared. 3. The ratios between Ca2+ uptake and ATP hydrolysis activities in the SHR remained approximately 1.0, showing a proportional reduction in both activities. 4. No difference in affinity for calmodulin was observed between SHR and WKY. 5. No significant difference in Ca2+-dependent ATP hydrolysis activity was observed between SHR and WKY after detergent solubilization of erythrocyte ghost membranes. 6. These results suggest that the number of Ca2+-Mg2+-ATPase units are similar in SHR and WKY and that the reduced activity in the intact SHR membrane is due to altered membrane environment.