ISSN:
1432-2013
Keywords:
Spontaneously hypertensive rat
;
Calcitonin
;
1,25-dihydroxycholecalciferol
;
Parathyroid hormone
;
Phosphate metabolism
;
Bone
Source:
Springer Online Journal Archives 1860-2000
Topics:
Medicine
Notes:
Abstract In young spontaneously hypertensive rats (SHR) and in normotensive Wistar-Kyoto controls (WKY) several parameters of phosphate and calcium homeostasis were determined. At 6 and 8 weeks, blood analysis revealed a significant hypophosphatemia (p〈0.001) in SHR and twice as high plasma calcitonin levels in SHR than in WKY controls. At 8 weeks, 1,25-dihydroxycholecalciferol concentration was 20% higher in SHR (p〈0.02) while 25-hydroxycholecalciferol was unaltered (p〈0.51). In addition total immunoreactive PTH, iPTH, was slightly increased (p〈0.07) but intact PTH (1–84) (p〉0.90) was not significantly different from age matched WKY controls. Also at 8 weeks, a slightly reduced serum ionized Ca2+ concentration (p〈0.001) with no change in total serum calcium was found in SHR (p〉0.39). Balance studies at 6 and 8 weeks of age revealed no significantly different balances for phosphate (F=2.5,p〉0.10) and for calcium (F=2.6,p〉0.09), although a tendency for slightly more positive balaces existed in SHR when compared to WKY. However, SHR excreted significantly less phosphate in the urine than WKY control (F=0.2,p〈0.0009). Bone analysis was performed on femora of SHR and WKY of 6 weeks of age. Femora were significantly shorter in SHR (20.54±0.35 vs. 21.50±0.05 mm in WKY), whereas bone dry weight (127±6 vs. 107±2mg), bone ash weight (79±4 vs. 66±1 mg) and bone volume (0.196±0.007 vs. 0.165±0.004 cm3) were significantly greater in SHR. Calcium content per femur (717±35 vs. 617±11 μmol Ca/femur) and phosphate content per femur (512±23 vs. 447±8 μmol P/femur) were also significantly higher in SHR. It is discussed that the disturbances in phosphate homeostasis may be secondary to the strikingly increased plasma calcitonin levels present in young SHR.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00581135
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