Platelet calcium pump activity in essential hypertensives and their first-degree relatives.
Intracellular free Ca2+ concentration has been shown to be elevated in platelets of patients with essential hypertension. This study was designed to characterize Ca(2+)-pump activity of the platelet membranes (surface and intracellular) in these patients A double-blind study was carried out. Untreated and treated (on beta-blockers) essential hypertensives were studied in comparison with normotensive control subjects. First degree blood relatives of essential hypertensives were also studied. The Ca2+ activation kinetics of the enzyme showed a significant decrease in the Vmax (for the plasma- and intracellular membranes) and Km (for the intracellular membranes) in the essential hypertensive patients. Increased platelet membrane cholesterol content was observed in these patients. Lowered Ca2(+)-efflux by Ca2(+)-ATPase may lead to elevated intracellular free Ca2(+)-levels in platelet of essential hypertensives. A lowered Ca2(+) -ATPase activity may emerge as a marker for essential hypertension.
Gulati
S
S
Department of Experimental Medicine, Postgraduate Institute of Medical Education and Research, Chandigarh, India.
Khullar
M
M
Sharma
B K
BK
Ganguly
N K
NK
D000293:Adolescent; D000319:Adrenergic beta-Antagonists / Q000627:therapeutic use; D000328:Adult; D000959:Antihypertensive Agents / Q000627:therapeutic use; D015415:Biomarkers; D001792:Blood Platelets / Q000201:enzymology*; D002118:Calcium / Q000097:blood*; D000252:Calcium-Transporting ATPases / Q000378:metabolism*; D002784:Cholesterol / Q000097:blood; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D006973:Hypertension / Q000097:blood* / Q000188:drug therapy / Q000235:genetics; D007424:Intracellular Fluid / Q000737:chemistry; D008297:Male; D008563:Membrane Lipids / Q000097:blood; D008875:Middle Aged; D000254:Sodium-Potassium-Exchanging ATPase / Q000097:blood
D000319:Adrenergic beta-Antagonists; D000959:Antihypertensive Agents; D015415:Biomarkers; D008563:Membrane Lipids; D002784:Cholesterol; D000252:Calcium-Transporting ATPases; D000254:Sodium-Potassium-Exchanging ATPase; D002118:Calcium