title: Serum-mediated intracellular calcium changes in normotensive and hypertensive red blood cells: role of parathyroid hypertensive factor.
abstract: To study cellular calcium metabolism in hypertension, we investigated the effects of human serum, and of the circulating pressor substance, parathyroid hypertensive factor (PHF), on the cytosolic free calcium (Cai-f) content of erythrocytes from normotensive and essential hypertensive subjects. In their own serum, basal Cai-f was higher in hypertensive than in normotensive and essential hypertensive subjects. In their own serum, basal Cai-f was higher in hypertensive than in normotensive subjects (mean +/- SEM; 39.4 +/- 4.0 vs. 23.4 +/- 2.7 nM; p < 0.05). Without serum, Cai-f was lower and not significantly different (23.0 +/- 3.1 vs. 18.2 +/- 2.7 nM; p = not significant). Addition of serum to serum-free erythrocytes increased Cai-f, and reestablished the Cai-f gradient in hypertensive cells (31.4 +/- 0.8 vs 23.0 +/- 2.3 nM; p < 0.05). PHF levels were directly related to basal Cai-f (r = -0.648; p < 0.05) and to the serum-induced rise in Cai-f (r = 0.600; p < 0.05). Furthermore, semipurified PHF, but not similarly prepared normotensive serum, increased Cai-f in normal human erythrocytes (PHF: +83.9 +/- 37.3% vs. +14.5 +/- 27.5%; p < 0.05). We conclude that circulating factors in general, and PHF in particular, may account for the increased basal Cai-f of hypertension, and thus at least partially contribute to te pathophysiology of the hypertensive process.
authors.affiliation: Cardiovascular Center, New York Hospital-Cornell Medical Center, New York.
authors.forename: M
authors.initials: M
authors.lastname: Barbagallo
authors.forename: R K
authors.initials: RK
authors.lastname: Gupta
authors.forename: R Z
authors.initials: RZ
authors.lastname: Lewanczuk
authors.forename: P K
authors.initials: PK
authors.lastname: Pang
authors.forename: L M
authors.initials: LM
authors.lastname: Resnick
mesh_terms: D000368:Aged; D000818:Animals; D001685:Biological Factors / Q000494:pharmacology*; D002118:Calcium / Q000097:blood*; D003600:Cytosol / Q000378:metabolism; D004912:Erythrocytes / Q000378:metabolism*; D005260:Female; D006801:Humans; D006973:Hypertension / Q000097:blood*; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D008875:Middle Aged; D051381:Rats; D011918:Rats, Inbred SHR; D011921:Rats, Inbred WKY
chemical_list: D001685:Biological Factors; C064505:parathyroid hypertensive factor; D002118:Calcium