caa a22 4500 469078480 CHVBK 20180323132942.0 cr unu---uuuuu 170328e19921101xx s 000 0 eng 10.1007/BF00169011 doi (NATIONALLICENCE)springer-10.1007/BF00169011 Three levels of dietary calcium-effects on blood pressure and electrolyte balance in spontaneously hypertensive rats [Elektronische Daten] [Heikki Wuorela, Ilkka Pörsti, Pertti Arvola, Heikki Mäkynen, Heikki Vapaatalo] Summary: The effects of three levels of calcium intake on blood pressure (BP) and electrolyte balance were studied for 12 weeks in spontaneously hypertensive rats (SHR): the chow of the SHR-1 group contained 1.1% calcium, and that of the supplemented groups 2.1% (SHR-2) and 3.1% (SHR-3) calcium. Wistar-Kyoto rats on a 1.1% calcium diet (WKY-1) served as normotensive controls. After 10 and 12 weeks BP was significantly lower in both calcium-supplemented groups than in the SHR-1 group, the SHR-2 and SHR-3 groups not deviating from each other. Platelets and lymphocytes were used as experimental cell models to study the effects of the calcium diets on intracellular free calcium ([Ca2+]i) level, which was measured by the fluorescent indicator quin-2. At the end of the study [Ca2+]i was lower in both cell types in SHR-2 and SHR-3 than in SHR-1, the supplemented groups being comparable to each other. In platelets [Ca2+]i still remained higher in the calcium-treated than the WKY-1 group, while in lymphocytes the levels were similar between SHR-2, SHR-3 and WKY-1. Plasma sodium, calcium and magnesium levels did not differ in the SHR groups, but plasma potassium was higher in both supplemented groups than in SHR-1. Plasma renin activity was comparable in SHR-1, SHR-2 and WKY-1, but was suppressed in the SHR-3 group. Creatinine clearance in the SHR-3 group was higher than in SHR-1 and SHR-2, but still remained lower than in WKY 1. High calcium intake was associated with a dose-dependent increase in urinary magnesium excretion, while the excretions of sodium and potassium were proportional to the intakes. The tissue Na+ :K+ ratio in abdominal aorta and tail artery was reduced in SHR-2,.but only a nonsignificant tendency was observed in SHR-3 when compared with the SHR-1 group. In summary, high calcium intake reduces [Ca2+]i in both platelets and lymphocytes in SHR, suggesting that alterations in cellular calcium regulation may explain the BP-lowering effect of calcium supplementation. Elevation of dietary calcium level from 1.1% to 2.1% is associated with a lowering of the Na+ :K+ ratio in the arterial wall. A further increase in calcium content from 2.1% to 3.1% appears to have a favourable effect on renal function in SHR, but also aggravates magnesium loss into the urine. During the higher supplemented calcium intake, suppression of the renin-angiotensin system seems to be involved in the lowering of BP. Springer-Verlag, 1992 Blood pressure nationallicence High calcium intake nationallicence Intracellular free calcium nationallicence Na+ :K+ ratio nationallicence Spontaneously hypertensive rats nationallicence Wuorela Heikki Department of Biomedical Sciences, University of Tampere, P.O. Box 607, SF-33101, Tampere, Finland aut Pörsti Ilkka Department of Biomedical Sciences, University of Tampere, P.O. Box 607, SF-33101, Tampere, Finland aut Arvola Pertti Department of Biomedical Sciences, University of Tampere, P.O. Box 607, SF-33101, Tampere, Finland aut Mäkynen Heikki Department of Biomedical Sciences, University of Tampere, P.O. Box 607, SF-33101, Tampere, Finland aut Vapaatalo Heikki Department of Biomedical Sciences, University of Tampere, P.O. Box 607, SF-33101, Tampere, Finland aut Naunyn-Schmiedeberg's Archives of Pharmacology Springer-Verlag 346/5(1992-11-01), 542-549 0028-1298 346:5<542 1992 346 210 https://doi.org/10.1007/BF00169011 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF00169011 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Wuorela Heikki Department of Biomedical Sciences, University of Tampere, P.O. Box 607, SF-33101, Tampere, Finland aut NATIONALLICENCE 700 1- Pörsti Ilkka Department of Biomedical Sciences, University of Tampere, P.O. Box 607, SF-33101, Tampere, Finland aut NATIONALLICENCE 700 1- Arvola Pertti Department of Biomedical Sciences, University of Tampere, P.O. Box 607, SF-33101, Tampere, Finland aut NATIONALLICENCE 700 1- Mäkynen Heikki Department of Biomedical Sciences, University of Tampere, P.O. Box 607, SF-33101, Tampere, Finland aut NATIONALLICENCE 700 1- Vapaatalo Heikki Department of Biomedical Sciences, University of Tampere, P.O. Box 607, SF-33101, Tampere, Finland aut NATIONALLICENCE 773 0- Naunyn-Schmiedeberg's Archives of Pharmacology Springer-Verlag 346/5(1992-11-01), 542-549 0028-1298 346:5<542 1992 346 210 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer