scholarly journals Differentiation of the changes in alkaline phosphatase from calcium ion-activated adenosine triphosphatase activities associated with increased calcium absorption in chick intestine

1978 ◽  
Vol 174 (3) ◽  
pp. 1067-1070 ◽  
Author(s):  
S M Lane ◽  
D E M Lawson
Keyword(s):  
Vitamin D ◽  
Alkaline Phosphatase ◽  
Calcium Ion ◽  
Adenosine Triphosphatase ◽  
Calcium Absorption ◽  
Intestinal Enzymes ◽  
Dependent Absorption ◽  
Calcium Ion Activated

The pattern of response of the intestinal enzymes Ca2+-activated adenosine triphosphatase and alkaline phosphatase in the chick to 1,25-dihydroxycholecalciferol is consistent with a role for the former but not the latter enzyme in the vitamin D-dependent absorption of calcium.

Role of prolactin in vitamin D metabolism and calcium absorption during lactation in the rat

1982 ◽  
Vol 94 (3) ◽  
pp. 443-453 ◽  
Author(s):  
C. J. Robinson ◽  
E. Spanos ◽  
M. F. James ◽  
J. W. Pike ◽  
M. R. Haussler ◽  
...  
Keyword(s):  
Vitamin D ◽  
Alkaline Phosphatase ◽  
Parathyroid Hormone ◽  
Alkaline Phosphatase Activity ◽  
Plasma Levels ◽  
Calcium Absorption ◽  
High Plasma ◽  
Intestinal Calcium Absorption ◽  
Vitamin D Metabolism

Intestinal calcium absorption and plasma levels of 1,25-dihydroxycholecalciferol (1,25(OH)2D3) were measured in lactating and non-lactating rats and the effects of bromocriptine and exogenous prolactin treatment were evaluated. In lactating rats calcium absorption and plasma levels of parathyroid hormone, 1,25(OH)2D3 and alkaline phosphatase activity were significantly increased. Bromocriptine treatment significantly reduced the enhanced calcium absorption and levels of plasma 1,25(OH)2D3 and alkaline phosphatase but had no significant effect on plasma levels of parathyroid hormone. Prolactin administered with bromocriptine to lactating animals prevented all the changes observed with bromocriptine treatment alone. It was concluded that the increased plasma levels of prolactin during lactation lead to high plasma levels of 1,25(OH)2D3 which are responsible for the enhanced intestinal calcium absorption.

OCCULT MALABSORPTION CAUSING OSTEITIS FIBROSA CYSTICA

1962 ◽  
Vol 40 (4) ◽  
pp. 481-492
Author(s):  
J. G. Devlin ◽  
D. K. O'Donovan
Keyword(s):  
Vitamin D ◽  
Iron Absorption ◽  
Calcium Absorption ◽  
Calcium Balance ◽  
Gluten Free ◽  
Osteitis Fibrosa Cystica ◽  
Mucosal Atrophy ◽  
Cystic Changes ◽  
Calcium Malabsorption ◽  
Radiological Examinations

ABSTRACT A case is reported of intermittent hypercalcaemia, hypophosphataemia and severe skeletal rarefaction with cystic changes. An occult calcium malabsorption was found. Fat, triolein and iron absorption and radiological examinations were normal. There was gross intestinal mucosal atrophy. She was shown to be in a state of negative calcium balance and this was reversed by vitamin D. A gluten-free diet also improved calcium absorption. It is postulated that the patient had severe secondary hyperparathyroidism as the skeleton reverted to normal after six months of medical treatment.

scholarly journals New insights into vitamin D regulation: is there a role for alkaline phosphatase?

2021 ◽  
Author(s):  
G. Bellastella ◽  
L. Scappaticcio ◽  
M. Longo ◽  
R. Carotenuto ◽  
C. Carbone ◽  
...  
Keyword(s):  
Vitamin D ◽  
Alkaline Phosphatase ◽  
Liver Function ◽  
Significant Negative Correlation ◽  
Liver Function Tests ◽  
Bone Alkaline Phosphatase ◽  
Gamma Glutamyl Transpeptidase ◽  
Function Tests ◽  
Group 2 ◽  
Group 1

Abstract Purpose The diagnosis of vitamin D deficiency is based on the determination of total plasma 25-hydroxyvitamin D (25-OHD) concentrations, but the regulation of vitamin D 25-hydroxylation is not a major consideration and very little information is available on this activity. To check what factors could interfere with the activity of vitamin D-25-hydroxylase and thus alter the 25-OHD concentrations, we looked for potential correlations between 25-OHD and results of liver function tests in healthy adults. Methods This single-centre study was retrospective and consisted of evaluating the correlations between 25-OHD and the activities of aspartate aminotransferase (AST), alanine aminotransferase (ALT), gamma-glutamyl transpeptidase (GGT), alkaline phosphatase (ALP), and bone alkaline phosphatase (BALP) in 349 healthy subjects aged from 18 to 65 years. In particular, in Group 1 (n = 119), we looked for correlations between 25OHD and all liver function tests and in Group 2 (n = 230) the correlation between 25OHD and BALP. Results In Group 1, we found no correlation between 25OHD and AST (r =  − 0.03; p = 0.8), ALT (r =  − 0.02; p = 0.91), GGT (r =  − 0.08; p = 0.68), direct bilirubin (r =  − 0.02; p = 0.89), indirect bilirubin (r =  − 0.24; p = 0.21), and total bilirubin (r =  − 0.24; p = 0.21) but one between 25OHD and ALP (r =  − 0.2; p = 0.007); in Group 2, we found a significant negative correlation between 25-OHD and BALP (r =  − 0.2; p = 0.0008). Conclusions The correlations that we found suggest that ALP and BALP might be involved in the regulation of vitamin D-25-hydroxylase activity, but further studies are mandatory to confirm our assumptions.

scholarly journals Opposite correlation of 25-hydroxy-vitamin D- and 1,25-dihydroxy-vitamin D-metabolites with gestational age, bone- and lipid-biomarkers in pregnant women

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Oleg Tsuprykov ◽  
Saban Elitok ◽  
Claudia Buse ◽  
Chang Chu ◽  
Bernhard Karl Krämer ◽  
...  
Keyword(s):  
Vitamin D ◽  
Alkaline Phosphatase ◽  
Pregnant Women ◽  
Clinical Chemistry ◽  
Water Soluble ◽  
Target Cells ◽  
Vitamin D Metabolites ◽  
Specific Alkaline Phosphatase ◽  
Bone Specific Alkaline Phosphatase ◽  
Group B

Abstract25-Hydroxyvitamin D (25OHD) and 1,25-dihydroxyvitamin D (1,25(OH)2D) need to be bound to carrier proteins to be transported to their target cells. The majority of either 25OHD or 1,25(OH)2D is bound to vitamin D-binding protein (DBP), a smaller fraction is bound to albumin and only very small amounts of 25OHD or 1,25(OH)2D are free. Albumin-bound 25OHD or 1,25(OH)2D is relatively easily available after dissociation from albumin. Thus, the sum of free and albumin-bound forms is called bioavailable 25OHD and bioavailable 1,25(OH)2D. Total 25OHD and 1,25(OH)2D are defined as the sum of free, albumin-bound and DBP-bound 25OHD and 1,25(OH)2D, respectively. This cross-sectional study in 427 pregnant women compared the correlation of the six vitamin D compounds with biomarkers of bone health, lipid metabolism, kidney function, endocrine parameters, and group B water-soluble vitamins. Among the 25OHD metabolites analysed, total 1,25(OH)2D showed clearly the best correlation with calcium, bone-specific alkaline phosphatase, adiponectin, LDL, HDL, urea, thyroxine, and group B water-soluble vitamins. When comparing the three 25OHD metabolites, both free 25OHD and bioavailable 25OHD showed overall good correlations with calcium, bone-specific alkaline phosphatase, adiponectin, LDL, HDL, urea, thyroxine, triiodothyronine, and group B water-soluble vitamins, The correlations of 1,25(OH)2D and 25OHD metabolites went always in opposite directions. Only PTH correlates always inversely with all six vitamin D compounds. In conclusion, free 25(OH)D and bioavailable 25(OH)D are more precise determinants of the vitamin D status than total 25(OH)D in normal pregnancy, whereas total 1,25(OH)2D is superior to free and bioavailable 1,25(OH)2D. Except for PTH, correlations of 25(OH)D and 1,25(OH)2D metabolites with typical clinical chemistry readouts go in opposite directions.

Fibroblast growth factor 23 and its role in phosphate homeostasis in growing children compared to adults

2020 ◽  
Vol 33 (8) ◽  
pp. 1065-1071
Author(s):  
Marjan Jeddi ◽  
Maryam Heidari ◽  
Neda Hatami ◽  
Gholam Hossein Ranjbar Omrani
Keyword(s):  
Vitamin D ◽  
Alkaline Phosphatase ◽  
Fibroblast Growth Factor 23 ◽  
Fractional Excretion ◽  
Cross Sectional Study ◽  
Fibroblast Growth ◽  
Sectional Study ◽  
Phosphate Homeostasis ◽  
Cross Sectional ◽  
Fractional Excretion Of Phosphate

AbstractObjectivesPhosphate is essential for skeletal mineralization, which is regulated by parathyroid hormone, calcitriol and fibroblast growth factor 23 (FGF23). Serum phosphate is physiologically higher in younger children, but factors that contribute to this physiological state are poorly understood. This study aimed to evaluate phosphate and its regulators in children compared with adults.Materials and methodsThe participants were children aged 3–11 years and adults older than 20 years of age. Biochemical parameters including calcium, phosphorus, alkaline phosphatase, FGF23, and vitamin D were measured. Fractional excretion of phosphate was calculated, using serum and urine phosphate and creatinine.ResultsThis cross-sectional study was conducted on 45 children (mean age: 9.0 ± 2.1) and 44 adults (mean age: 38.9 ± 11.1). The children had higher serum calcium, phosphate, alkaline phosphatase, and FGF23 (p < 0.001), but fractional excretion of phosphate was greater in adults (14.1 ± 5.7, 11.4 ± 4.4, p = 0.019, 95% confidence interval [CI]: −0.7 to −0.2). Of all individuals, 61.8% had vitamin D deficiency. By multiple regression analysis, entering age, calcium, phosphate, and vitamin D level, the only independent predictor of FGF23 was 1, 25 dihydroxy-vitamin D3 (β: 0.78, p < 0.001, 95% CI: 0.5–1.1, R2: 0.59 for children, and β: 0.59, p < 0.001, 95% CI: 0.5–1.4, R2: 0.45 for adults).ConclusionAs far as we know, there is little information regarding the role of FGF23 in physiologic state. In this cross-sectional study no association was found between FGF23 and urinary phosphate excretion in growing children. Further studies with more detail are essential to evaluate phosphate homeostasis during childhood.

Calcium absorption and vitamin D in the chick

1951 ◽  
Vol 34 (1) ◽  
pp. 105-111 ◽  
Author(s):  
B.B. Migicovsky ◽  
A.M. Nielson
Keyword(s):  
Vitamin D ◽  
Calcium Absorption

scholarly journals Inhibition studies of alkaline phosphatase in hard tissue-forming cells.

1975 ◽  
Vol 23 (5) ◽  
pp. 342-347 ◽  
Author(s):  
A Linde ◽  
B C Magnusson
Keyword(s):  
Alkaline Phosphatase ◽  
Enzyme Activity ◽  
Adenosine Triphosphatase ◽  
Ruthenium Red ◽  
Inorganic Pyrophosphatase ◽  
Alkaline Ph ◽  
Hard Tissue ◽  
Assay Condition ◽  
Phosphatase Inhibitors ◽  
Inhibition Studies

The effects of the alkaline phosphatase inhibitors levamisole and R 8231 on p-nitro-phenylphosphatase, inorganic pyrophosphatase and adenosine triphosphatase (ATPase) activities in dentingenically active odontoblasts were studied. The p-nitrophenylphosphatase and inorganic pyrophosphatase activities were inhibited, while 40% of the ATP-splitting enzyme activity remained under the assay condition used. This finding, togeather with earlier studies, indicates that at least two different phosphatase are active at alkaline pH in hard tissue-forming cells; on nonspecific alkaline phosphatase and one specific ATPase. The ATPase activity is uninfluenced by ouabain and ruthenium red and is activated by Ca-2+ ions.

The Temporal Distribution of the 1α,25-Dihydroxycholecalciferol Receptor in the Rat Jejunal Villus

1984 ◽  
Vol 67 (3) ◽  
pp. 285-290 ◽  
Author(s):  
S. D. H. Chan ◽  
D. Atkins
Keyword(s):  
Vitamin D ◽  
Vitamin D Deficiency ◽  
Calcium Absorption ◽  
Sedimentation Coefficient ◽  
Temporal Distribution ◽  
High Affinity ◽  
High Affinity Receptor ◽  
Affinity Receptor ◽  
Cell Fractions ◽  
Crypt Cells

1. The distribution of the 1α,25-dihydroxycholecalciferol receptor was studied in enterocytes isolated from the upper, mid and lower villus and crypt cells of the jejunum of normal and rachitic rats. 2. In all cell fractions a high-affinity receptor (KD ⋍ 0.07 nmol/l) with a sedimentation coefficient of 3.5S was demonstrated. 3. In normal rats there was a 60% reduction in receptor numbers in crypt cells compared with the mid and upper villous cells. 4. Vitamin D deficiency led to a reduction in receptor numbers in all cell fractions (45% upper villus, 78% crypt cells). 5. The data are compatible with the concept of calcium absorption occurring in the differentiated villous cells and also account for the reduction in absorption in rachitic animals.

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