Unidirectional duodenal and jejunal calcium and phosphorus transport in the rat: Effects of dietary phosphorus depletion, ethane-1-hydroxy-1,1-diphosphonate and 1,25 dihydroxycholecalciferol

1989 ◽  
Vol 189 (6) ◽  
pp. 439-449 ◽  
Author(s):  
H. Jungbluth ◽  
U. Binswanger
Keyword(s):  
Phosphorus Transport ◽  
Dietary Phosphorus ◽  
Calcium And Phosphorus ◽  
Phosphorus Depletion

scholarly journals The influence of dietary phosphorus intake on the rate of bone metabolism in sheep

1966 ◽  
Vol 20 (4) ◽  
pp. 727-732 ◽  
Author(s):  
V. R. Young ◽  
J. R. Luick ◽  
G. P. Lofgreen
Keyword(s):  
Bone Metabolism ◽  
Turnover Rates ◽  
Isotope Techniques ◽  
Dietary Phosphorus ◽  
Exchangeable Ca ◽  
Dietary Phosphorus Intake ◽  
Phosphorus Depletion ◽  
Phosphorus Intake ◽  
P Depletion ◽  
Calcium Pool

1. A combination of balance and isotope techniques was used to determine the influence of phosphorus depletion on the size of the exchangeable calcium pool and on the rates of Ca deposition in and removal from the whole skeleton of sheep. 2. The exchangeable Ca pool was reduced in size in the depleted sheep to approximately 50% of that in the controls. 3. The rates of Ca deposition in and removal from bone were reduced by P depletion and the rate of Ca transfer from the pool was reduced slightly. 4. The turnover rates of the exchangeable Ca pool and bone Ca in sheep appear to be similar to values published for man.

The flow of calcium and phosphorus in the digestive tract of the sheep

1974 ◽  
Vol 25 (1) ◽  
pp. 147 ◽  
Author(s):  
J Leibholz
Keyword(s):  
Calcium Intake ◽  
Energy Content ◽  
Calcium Content ◽  
Metabolizable Energy ◽  
Dietary Calcium Intake ◽  
Dietary Phosphorus ◽  
Calcium And Phosphorus ◽  
Dietary Phosphorus Intake ◽  
The One ◽  
Phosphorus Intake

The flow of calcium and phosphorus to the proximal duodenum was measured over 22 24-hr periods in sheep fitted with re-entrant duodenal cannulae. The sheep were offered one of six diets in a ground and pelleted form supplying 1.4–30 g of nitrogen per day from three different protein sources. The estimated metabolizable energy content of the diets was 1.9 or 1.3 Mcal/kg. The diets supplied 2.0–5.8 g of calcium per day and 2.2–3.3 g of phosphorus per day. Between 49.9% and 61.2% of the dietary calcium intake appeared at the duodenum in the sheep given all diets except the one supplying 1.4 g of nitrogen per day, where the value was 98.5%. There were highly significant correlations between the daily calcium intake and the flow of calcium to the duodenum, the excretion of calcium in the faeces, the retention of calcium and the calcium content of the rumen. Between 85.0 and 119.1% of the daily phosphorus intake appeared at the duodenum in the sheep given all six diets. The flow of phosphorus was correlated with the dietary phosphorus intake. There were significant correlations between the flow of calcium and phosphorus to the duodenum and, also, their retention.

Mineral Balance Studies with the Baby Pig: Effects of Dietary Phosphorus Level upon Calcium and Phosphorus Balance

1964 ◽  
Vol 82 (1) ◽  
pp. 111-114 ◽  
Author(s):  
E. R. Miller ◽  
D. E. Ullrey ◽  
C. L. Zutaut ◽  
J. A. Hoefer ◽  
R. W. Luecke
Keyword(s):  
Phosphorus Level ◽  
Phosphorus Balance ◽  
Mineral Balance ◽  
Dietary Phosphorus ◽  
Calcium And Phosphorus

scholarly journals Effect of dietary phosphorus supplementation on the uptake of radioactive strontium in rats

1966 ◽  
Vol 20 (3) ◽  
pp. 561-569 ◽  
Author(s):  
G. E. Harrison ◽  
G. R. Howells ◽  
Jill Pollard ◽  
Krista Kostial ◽  
R. Manitaševi´c
Keyword(s):  
Experimental Evidence ◽  
Dietary Supplement ◽  
Normal Growth ◽  
Basal Diet ◽  
Remedial Measure ◽  
Adult Rats ◽  
Dietary Phosphorus ◽  
Ca Deficiency ◽  
Weanling Rats ◽  
Calcium And Phosphorus

1. After feeding radioactive markers 85Sr and 45Ca for 10 days to weanling and adult rats receiving basal diets all of which contained adequate calcium and phosphorus to support normal growth, the skeletal retention of the markers was compared with that in litter-mates receiving seven different P compounds as dietary supplements so that the P intake was increased 2 to 3½ times. 2. In weanling rats a dietary supplement of KH2PO4 decreased the skeletal retention of 85Sr by some 30% without affecting the retention of 46Ca. In adults on this supplement, the skeletal retention of 85Sr was reduced by over 40% compared with controls on the same basal diet. 3. When the supplement contained Ca as well as P the reduction in skeletal retention of 85Sr in young and adult rats was greater than when no Ca was present in the supplement. 4. It is concluded that there was no experimental evidence to show that supplements of P which also contained Ca induced any Ca deficiency in the rats. 5. In rats receiving P supplements which also contained Ca, the ratio of the skeletal retention of 85Sr, experimental to controls, was 0.45 for weanling rats and 0.52 in adults, 34 weeks old. These ratios were not significantly different for any of the seven supplements used. 6. From comparisons with previous experiments, it is concluded that supplementation with Ca plus P is more promising as a remedial measure for decreasing the uptake of radioactive Sr from the diet than supplementation with Ca alone.

The calcimimetic AMG 641 accelerates regression of extraosseous calcification in uremic rats

2009 ◽  
Vol 296 (6) ◽  
pp. F1376-F1385 ◽  
Author(s):  
Ignacio Lopez ◽  
Francisco J. Mendoza ◽  
Fatima Guerrero ◽  
Yolanda Almaden ◽  
Charles Henley ◽  
...  
Keyword(s):  
Phosphorus Content ◽  
Urinary Calcium ◽  
Calcium Excretion ◽  
Phagocytic Cells ◽  
Calcium Sensing Receptor ◽  
Calcium Sensing ◽  
Dietary Phosphorus ◽  
Tissue Calcium ◽  
Calcium And Phosphorus ◽  
Phosphorus Intake

The purpose of the present study was to test the hypothesis that extraskeletal calcification regresses in uremic rats after reduction in phosphorus intake and treatment with calcimimetics. Extraosseous calcification was induced in five to six nephrectomized rats fed a high-phosphorus (1.2%) diet who received calcitriol (80 ng/kg ip) every other day for a period of 14 days. Next, dietary phosphorus was reduced to 0.6%, and rats were treated with vehicle ( n = 20), calcitriol [80 ng/kg ip/48 h ( n = 20)], or the calcimimetic AMG 641 [1.5 mg/kg sc/48 h ( n = 20)]. Aortic and soft-tissue calcium and phosphorus content was evaluated after 14 and 28 days. At 28 days, reduction of phosphorus intake resulted in a significant decrease in tissue mineral content in vehicle- and AMG 641-treated rats but not in rats receiving calcitriol. Aortic calcium and phosphorus was lower in rats treated with AMG 641 (96.7 ± 26.4 mg/g) than in rats receiving vehicle (178.3 ± 38.6 mg/g). An infiltrate of phagocytic cells expressing the calcium-sensing receptor was identified in areas surrounding foci of calcification. Additional studies in parathyroidectomized rats demonstrated that AMG 641 increased the urinary excretion of calcium (6.2 ± 0.6 vs. 3.1 ± 0.5 mg/day, vehicle) ( P < 0.001). In conclusion, experimentally induced extraosseous calcification in uremic rats can be partially resolved by reducing phosphorus intake; the addition of calcimimetics may accelerate the regression process through mechanisms potentially involving a direct stimulatory effect on mineral phagocytic cells plus an increase in urinary calcium excretion.

scholarly journals Interactions between calcium and phosphorus in the regulation of the production of fibroblast growth factor 23 in vivo

2013 ◽  
Vol 304 (3) ◽  
pp. E310-E320 ◽  
Author(s):  
Stephen J. Quinn ◽  
Alex R. B. Thomsen ◽  
Jian L. Pang ◽  
Lakshmi Kantham ◽  
Hans Bräuner-Osborne ◽  
...  
Keyword(s):  
Serum Calcium ◽  
Fibroblast Growth Factor 23 ◽  
Threshold Level ◽  
Serum Levels ◽  
Serum Phosphorus ◽  
Dihydroxyvitamin D ◽  
Dietary Phosphorus ◽  
Calcium Phosphorus ◽  
Calcium And Phosphorus

Calcium and phosphorus homeostasis are highly interrelated and share common regulatory hormones, including FGF23. However, little is known about calcium's role in the regulation of FGF23. We sought to investigate the regulatory roles of calcium and phosphorus in FGF23 production using genetic mouse models with targeted inactivation of PTH (PTH KO) or both PTH and the calcium-sensing receptor (CaSR; PTH-CaSR DKO). In wild-type, PTH KO, and PTH-CaSR DKO mice, elevation of either serum calcium or phosphorus by intraperitoneal injection increased serum FGF23 levels. In PTH KO and PTH-CaSR DKO mice, however, increases in serum phosphorus by dietary manipulation were accompanied by severe hypocalcemia, which appeared to blunt stimulation of FGF23 release. Increases in dietary phosphorus in PTH-CaSR DKO mice markedly decreased serum 1,25-dihydroxyvitamin D3 [1,25(OH)2D3] despite no change in FGF23, suggesting direct regulation of 1,25(OH)2D3 synthesis by serum phosphorus. Calcium-mediated increases in serum FGF23 required a threshold level of serum phosphorus of about 5 mg/dl. Analogously, phosphorus-elicited increases in FGF23 were markedly blunted if serum calcium was less than 8 mg/dl. The best correlation between calcium and phosphorus and serum FGF23 was found between FGF23 and the calcium × phosphorus product. Since calcium stimulated FGF23 production in the PTH-CaSR DKO mice, this effect cannot be mediated by the full-length CaSR. Thus the regulation of FGF23 by both calcium and phosphorus appears to be fundamentally important in coordinating the serum levels of both mineral ions and ensuring that the calcium × phosphorus product remains within a physiological range.

Effects of maleic acid on renal phosphorus transport: role of dietary phosphorus

1991 ◽  
Vol 261 (2) ◽  
pp. F227-F237
Author(s):  
J. Guntupalli ◽  
V. Delaney ◽  
E. J. Weinman ◽  
D. Lyle ◽  
M. Allon ◽  
...  
Keyword(s):  
Maleic Acid ◽  
Competitive Inhibition ◽  
Membrane Vesicle ◽  
Intraperitoneal Administration ◽  
Inhibitory Effect ◽  
Phosphorus Transport ◽  
Dietary Phosphorus ◽  
Pi Transport

The effects of maleic acid on renal phosphate (Pi) transport were examined by clearance and brush-border membrane vesicle (BBMV) transport studies. In normal rats, maleic acid 50 mg.kg body wt-1.h-1 increased the phosphaturia (P less than 0.001). Intraperitoneal administration of a similar dose of maleic acid decreased the BBMV uptake of Pi but not glucose. In rats fed a low-phosphate diet (0.03%), the maleic acid-induced phosphaturia was blunted, but the inhibitory effect on the BBMV transport of Pi persisted. In chronic parathyroidectomized rats fed a low-phosphate diet, where the filtered load of Pi was higher than in the previous groups, the phosphaturia was abolished, but the inhibition of the BBMV transport of Pi was sustained. Both the in vitro incubation of BBMVV and in vivo administration of maleic acid were associated with a competitive inhibition of Pi transport. These studies indicate that the maleic acid-induced phosphaturia is expressed at the apical membrane entry step of Pi, and the enhanced distal tubular reabsorption accounts for the lack of phosphaturia in dietary Pi deprivation.

Dietary phosphorus depletion in sheep: effects on plasma inorganic phosphorus, calcium, l,25-(OH)2-Vit.D3 and alkaline phosphatase and on gastrointestinal P and Ga balances

1985 ◽  
Vol 105 (3) ◽  
pp. 623-629 ◽  
Author(s):  
G. Breves ◽  
R. Ross ◽  
H. Höller
Keyword(s):  
Alkaline Phosphatase ◽  
Plasma Concentrations ◽  
Inorganic Phosphorus ◽  
Free Fluid ◽  
Dietary Phosphorus ◽  
Flow Through ◽  
P Balance ◽  
Phosphorus Depletion ◽  
Total P ◽  
P Depletion

SUMMARYExperiments were carried out to study the effects of dietary P depletion on plasma concentrations of inorganic P (P1), calcium, 1,25-(OH)2-Vit.D3 and alkaline phosphatase, and to investigate the effects of P depletion, in comparison with P repletion, on intestinal flow and net disappearance of Ca and P in sheep. The animals were adapted to an experimental diet of pellets and chopped straw providing between 0·91 and 1·04 g P/day for depletion. They were repleted by single infusions of phosphate into the duodenum raising total P supply to about 4·1 g/day. During P depletion plasma P1, concentrations decreased significantly whereas those of Ca increased. The development of hypercalcaemia is discussed with respect to intestinal absorption and bone accretion and resorption. Plasma 1,25-(OH)2-Vit.D3 and alkaline phosphatase were not affected by P depletion.In P depletion the flow through the gastrointestinal tract of total P contained in the digesta and faecal P excretion were significantly reduced and the P balance was slightly negative. Calcium net absorption from the gut was also reduced. Daily flow of total P and P1, contained in the particle-free intestinal fluid was markedly lower in P depletion as compared with P repletion. The percentage of net disappearance from the small intestines of total P and P1, in the particle-free fluid was 57 and 70 % in the depleted state and 79 and 93% in the repleted state.

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