Raised levels of calcium-binding protein in plasma following insulin-induced hypoglycaemia in the pig

1986 ◽  
Vol 109 (1) ◽  
pp. 101-106 ◽  
Author(s):  
E. M. W. Maunder ◽  
A. V. Pillay ◽  
C. Chapman ◽  
A. D. Care
Keyword(s):  
Vitamin D ◽  
Calcium Binding ◽  
Inorganic Phosphate ◽  
Binding Protein ◽  
Plasma Concentrations ◽  
Calcium Binding Protein ◽  
Insulin Administration ◽  
Calcium Diet ◽  
Low Calcium Diet ◽  
Normal Calcium

ABSTRACT Insulin-induced hypoglycaemia in the pig elicited sharp increases in the plasma concentrations of vitamin D-dependent calcium-binding protein (CaBP) and cortisol and a decrease in plasma inorganic phosphate. Glucose infusion following insulin administration abolished the increases in plasma CaBP and cortisol in response to insulin and reduced the hypophosphataemia. The percentage increases in plasma CaBP and cortisol in response to insulin-induced hypoglycaemia were reduced when the pigs were fed a low-calcium diet, but the hypophosphataemic response was similar. We conclude that insulin-induced hypoglycaemia leads to increased plasma CaBP in pigs fed a normal calcium diet, which is associated with the hypoglycaemia rather than being a direct effect of insulin. We therefore suggest that plasma CaBP may represent more than a mere uncontrolled leak from its sites of storage. J. Endocr. (1986) 109, 101–106

Radioimmunoassay Studies of Intestinal Calcium-binding Protein in the Pig. I. Identification of Intestinal Calcium-binding Protein in Blood and Response to a Low Calcium Diet

1975 ◽  
Vol 53 (6) ◽  
pp. 1129-1134 ◽  
Author(s):  
B. M. Arnold ◽  
M. Kuttner ◽  
R. Swaminathan ◽  
A. D. Care ◽  
A. J. W. Hitchman ◽  
...  
Keyword(s):  
Small Intestine ◽  
Intestinal Mucosa ◽  
Calcium Binding ◽  
Binding Protein ◽  
Calcium Binding Protein ◽  
Intestinal Biopsy ◽  
Mixed Venous Blood ◽  
Calcium Diet ◽  
Low Calcium Diet ◽  
Low Calcium

We have developed a radioimmunoassay for porcine intestinal calcium-binding protein (CaBP) and have used it to detect CaBP in pig plasma. Plasma CaBP is identical to intestinal CaBP on the basis of immunological activity, molecular size, and molecular charge properties. The plasma CaBP concentration was greater in the portal blood than in mixed venous blood, suggesting that blood CaBP originates in the gut. Two of four 15-week-old littermate pigs were placed on a low calcium diet (0.15% calcium, 0.65% phosphorus) and two on a control diet (0.65% calcium, 0.65% phosphorus). After 2 weeks, the entire small intestine was removed and divided into nine 1.8-m segments. CaBP was assayed in both plasma and intestinal mucosa. When the two pigs on a low calcium diet were compared with two control pigs, there was a general increase in immunoreactive CaBP in both plasma and intestinal mucosa. However, there was no increment in immunoreactive CaBP in the first 1.8-m segment of small intestine. Seventy-one percent of the increment in CaBP occurred distal to the first two segments. The largest fractional low calcium diet effect occurred in the ileum. The mean CaBP concentration for the total small intestine increased by a factor of 1.9. The plasma CaBP concentration increased by a factor of 2.6. In these pigs, plasma CaBP was a more reliable indicator of change in CaBP status than was the measurement in the proximal gut segment which contained the duodenum. The assay of CaBP in blood is convenient and may obviate the sampling errors inherent in intestinal biopsy.

Regulation of intestinal calcium-binding protein calcium intake in the rat

1975 ◽  
Vol 228 (3) ◽  
pp. 861-869 ◽  
Author(s):  
T Freund ◽  
F Bronner
Keyword(s):  
Calcium Intake ◽  
Calcium Binding ◽  
Calcium Concentration ◽  
Binding Protein ◽  
Calcium Binding Protein ◽  
Competitive Binding Assay ◽  
Calcium Diet ◽  
Low Calcium Diet ◽  
Low Calcium ◽  
High Calcium

Analytical gel electrophoresis of the vitamin D-dependent intestinal calcium-binding protein (CaBP) has demonstrated two protein bands (1 and 2) of similar molecular weight and similar specific binding activity. The mucosal concentration of CaBP, measured by a quantitative competitive binding assay, has been shown to vary reproducibly and inversely with calcium intake and the mucosal calcium concentration. These same factors also influence the relationship of bands 1 and 2. When animals on a high-calcium diet were placed on a low-calcium diet, their CaBP increased by 35% in 24 h and by 48% in 48 h and reached a level typical of animals on a low-calcium diet. Measurement of the diurnal variation of CaBP and mucosal calcium in animals allowed access to feed only at night revealed significant, but inverse, oscillations. These observations are interpreted as reflecting a regulation of CaBP by the mucosal calcium concentration, which appears to reflect absorbed calcium in transit.

ROLE OF THE PARATHYROID GLANDS IN THE ENHANCEMENT OF INTESTINAL CALCIUM ABSORPTION IN RESPONSE TO A LOW CALCIUM DIET

1977 ◽  
Vol 74 (3) ◽  
pp. 345-354 ◽  
Author(s):  
J. FOX ◽  
R. SWAMINATHAN ◽  
T. M. MURRAY ◽  
A. D. CARE
Keyword(s):  
Small Intestine ◽  
Calcium Binding ◽  
Calcium Absorption ◽  
Binding Protein ◽  
Calcium Binding Protein ◽  
Intestinal Calcium Absorption ◽  
Parathyroid Glands ◽  
Calcium Diet ◽  
Low Calcium Diet ◽  
Low Calcium

SUMMARY The phenomenon of adaptation of intestinal calcium absorption to changes in dietary calcium has been studied in conscious pigs with Thiry–Vella jejunal loops. The result of decreasing the calcium content of the diet from 1·2 to 0·1% was an increase in the efficiency of the net absorption of calcium from the fluid used to perfuse the jejunal loop; this increase took place 4–6 days after the change in diet. A similar effect was noted in four pigs which had previously been parathyroidectomized and in two thyroparathyroidectomized pigs with thyroxine replacement therapy. The effect seen in the parathyroidectomized animals was not attributable to an increase in the concentration gradient of calcium ions between the jejunal lumen and the blood after the change to the low calcium diet. There was a marked increase in the amount of calcium-binding protein in the mucosa taken from the distal three-quarters of the small intestine of intact pigs fed a low calcium diet. However, after parathyroidectomy, the level of calcium in the diet had no significant effect on the amount of calcium-binding protein in the small intestine. It is concluded that, in pigs, neither parathyroid hormone nor calcitonin is necessary for intestinal adaptation to a low calcium diet and that, although this adaptation may be mediated by 1,25-dihydroxycholecalciferol, a significant increase in the level of calcium-binding protein in the intestine is only seen when the parathyroid glands are intact.

Effect of 1,25-dihydroxyvitamin D3 on plasma concentrations of calcium-binding protein in normal and rachitic (vitamin D-dependent rickets type I) pigs

1987 ◽  
Vol 115 (1) ◽  
pp. 129-134
Author(s):  
E. M. W. Maunder ◽  
A. V. Pillay ◽  
A. D. Care
Keyword(s):  
Vitamin D ◽  
Plasma Concentration ◽  
Calcium Binding ◽  
Binding Protein ◽  
Plasma Concentrations ◽  
Calcium Binding Protein ◽  
Type I ◽  
Dihydroxyvitamin D3 ◽  
Calbindin D ◽  
Permissive Role

ABSTRACT An i.v. injection of calcitriol (1,25-(OH)2D3) had no effect within 2·5 h on plasma concentrations of calbindin-D9k (vitamin D-induced calcium-binding protein; CaBP) in hypocalcaemic pigs with inherited vitamin D-dependent rickets type I or in their normocalcaemic siblings or half-siblings. Three days later the plasma concentration of CaBP had doubled in the hypocalcaemic pigs, but was unaltered in the normocalcaemic siblings and half-siblings. Following daily i.v. injections of 1,25-(OH)2D3 for a further 5 days (days 4–8) plasma concentrations of CaBP increased in both the hypocalcaemic (days 4–8) and normocalcaemic (day 8) pigs, the effect being more rapid and greater in the hypocalcaemic 1,25-(OH)2D3-deficient animals. An i.v. injection of 1,25-(OH)2D3 to pure Yucatan pigs also had no effect on plasma concentrations of CaBP within 1·5 h, but in the following 1 h there was some indication of an increase in plasma CaBP levels. In contrast to the normal pigs, insulin-induced hypoglycaemia did not lead to a peak in plasma CaBP concentrations in the hypocalcaemic pigs. There was also no change in the plasma concentrations of 1,25-(OH)2D3 associated with the peak in plasma CaBP following insulin-induced hypoglycaemia in normocalcaemic pigs. These results suggest that changes in plasma concentrations of 1,25-(OH)2D3 are not directly involved in mediating the increase in plasma CaBP which follows hypoglycaemia induced by insulin in normal pigs, although 1,25-(OH)2D3 probably plays a permissive role. J. Endocr. (1987) 115, 129–134

IMMUNOCYTOCHEMISTRY OF VITAMIN D-DEPENDENT CALCIUM BINDING PROTEIN IN CHICK PANCREAS: EXCLUSIVE LOCALIZATION IN B-CELLS.*

Endocrinology ◽  
1982 ◽  
Vol 110 (6) ◽  
pp. 2216-2218 ◽  
Author(s):  
JURGEN ROTH ◽  
SUSAN BONNER-WEIR ◽  
ANTHONY W. NORMAN ◽  
LELIO ORCI
Keyword(s):  
Vitamin D ◽  
B Cells ◽  
Calcium Binding ◽  
Binding Protein ◽  
Calcium Binding Protein

scholarly journals Vitamin D-dependent Calcium-binding Protein

1968 ◽  
Vol 243 (14) ◽  
pp. 3978-3986 ◽  
Author(s):  
R H Wasserman ◽  
R A Corradino ◽  
A N Taylor
Keyword(s):  
Vitamin D ◽  
Calcium Binding ◽  
Binding Protein ◽  
Calcium Binding Protein

scholarly journals Vitamin D-dependent Calcium-binding Protein

1968 ◽  
Vol 243 (14) ◽  
pp. 3987-3993 ◽  
Author(s):  
R H Wasserman ◽  
A N Taylor
Keyword(s):  
Vitamin D ◽  
Calcium Binding ◽  
Binding Protein ◽  
Calcium Binding Protein

scholarly journals In situ detection of vitamin D-induced calcium-binding protein (9-kDa CaBP) messenger RNA in rat duodenum.

1986 ◽  
Vol 34 (2) ◽  
pp. 277-280 ◽  
Author(s):  
M Warembourg ◽  
O Tranchant ◽  
C Perret ◽  
C Desplan ◽  
M Thomasset
Keyword(s):  
Vitamin D ◽  
In Situ Hybridization ◽  
Calcium Binding ◽  
Binding Protein ◽  
Cdna Probe ◽  
Calcium Binding Protein ◽  
Pbr322 Dna ◽  
Rat Duodenum ◽  
Columnar Cells

We have previously described the molecular cloning of a cDNA fragment synthesized from rat duodenal mRNA coding for a 9000-dalton vitamin D-induced calcium-binding protein (9-kDa CaBP) (3). We now report the use of this cloned cDNA to study the cytological distribution of 9-kDa CaBP mRNA in rat duodenum by in situ hybridization. Tissue sections, fixed in ethanol:acetic acid, were hybridized to the 3H-cDNA probe and processed for autoradiography. The specificity of the CaBP mRNA-DNA hybrid formation was checked using 3H-labeled plasmid pBR322 DNA as a control probe. 9k-Da CaBP mRNA, visualized by silver grains, was found only in the absorptive epithelial cells, and the concentration was greater in the cells at the villous tips than in those of the crypts. The 9k-Da CaBP mRNA was observed mainly in the cytoplasm of the columnar cells and less frequently in the nucleus. Labeling was not seen in the brush border and goblet cells. The submucosa, with Brunner's glands and muscularis, also showed no specific 9-kDa CaBP mRNA concentration. This demonstration of 9-kDa CaBP gene activity in the columnar cells of the rat duodenum illustrates the usefulness of in situ hybridization for characterization of specific cells involved in the expression of 1,25(OH)2 D3 activity.

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