Intestinal Absorption of Radiophosphate After Physiological Doses of 1,25-Dihydroxyvitamin D in Normals and Pathological Conditions

1979 ◽  
pp. 1015-1018
Keyword(s):  
Intestinal Absorption ◽  
Dihydroxyvitamin D ◽  
1,25 Dihydroxyvitamin D ◽  
Pathological Conditions

Effects of acute and chronic treatment with glucocorticoids on the intestinal absorption of calcium and phosphate and on plasma 1,25-dihydroxyvitamin D levels in pigs

1985 ◽  
Vol 69 (5) ◽  
pp. 553-559 ◽  
Author(s):  
John Fox ◽  
Richardus Ross ◽  
Anthony D. Care
Keyword(s):  
Intestinal Absorption ◽  
Plasma Levels ◽  
Time Course ◽  
Chronic Treatment ◽  
Intestinal Loop ◽  
Phosphate Absorption ◽  
Dihydroxyvitamin D ◽  
1,25 Dihydroxyvitamin D ◽  
Young Pigs ◽  
Proximal Small Intestine

1. We have used young pigs, each prepared surgically with a Thiry-Vella loop of proximal small intestine, to study the time course of changes in the intestinal absorption of calcium, phosphate, sodium, glucose and water and on the plasma levels of 1,25-dihydroxyvitamin D after treatment of the animals with glucocorticoids. 2. Perfusion of the intestinal loop for 6 h with a solution containing hydrocortisone or betamethasone was without effect on the absorption of calcium or phosphate. 3. The oral administration of betamethasone stimulated the absorption of calcium and phosphate by 15–20% for 2–3 days before the trend was reversed and absorption was progressively reduced. 4. Chronic treatment with betamethasone inhibited only the active component of calcium and phosphate absorption. 5. Treatment with betamethasone was associated with a sustained 25–50% increase, to a maximum by 2 days, in the absorption of sodium, glucose and water. 6. Plasma levels of 1,25-dihydroxyvitamin D were reduced within 2 days of the start of treatment and reached a minimum (40–50% decrease) in 4–6 days. 7. We conclude that the initial stimulation of calcium and phosphate absorption is caused by the increased absorption of water. The long-term decrease in absorption may not be caused solely by the decreased circulating levels of 1,25-dihydroxyvitamin D since absorption continued to fall for several weeks after 1,25-dihydroxyvitamin D levels had reached a minimum.

scholarly journals Regulation and Function of the FGF23/Klotho Endocrine Pathways

2012 ◽  
Vol 92 (1) ◽  
pp. 131-155 ◽  
Author(s):  
Aline Martin ◽  
Valentin David ◽  
L. Darryl Quarles
Keyword(s):  
Vitamin D ◽  
Intestinal Absorption ◽  
Mineral Metabolism ◽  
Bone Mineralization ◽  
Phosphate Homeostasis ◽  
Dihydroxyvitamin D ◽  
1,25 Dihydroxyvitamin D ◽  
Tubular Phosphate Reabsorption ◽  
Renal Tubular ◽  
And Function

Calcium (Ca2+) and phosphate (PO43−) homeostasis are coordinated by systemic and local factors that regulate intestinal absorption, influx and efflux from bone, and kidney excretion and reabsorption of these ions through a complex hormonal network. Traditionally, the parathyroid hormone (PTH)/vitamin D axis provided the conceptual framework to understand mineral metabolism. PTH secreted by the parathyroid gland in response to hypocalcemia functions to maintain serum Ca2+ levels by increasing Ca2+ reabsorption and 1,25-dihydroxyvitamin D [1,25(OH)2D] production by the kidney, enhancing Ca2+ and PO43− intestinal absorption and increasing Ca2+ and PO43− efflux from bone, while maintaining neutral phosphate balance through phosphaturic effects. FGF23 is a recently discovered hormone, predominately produced by osteoblasts/osteocytes, whose major functions are to inhibit renal tubular phosphate reabsorption and suppress circulating 1,25(OH)2D levels by decreasing Cyp27b1-mediated formation and stimulating Cyp24-mediated catabolism of 1,25(OH)2D. FGF23 participates in a new bone/kidney axis that protects the organism from excess vitamin D and coordinates renal PO43− handling with bone mineralization/turnover. Abnormalities of FGF23 production underlie many inherited and acquired disorders of phosphate homeostasis. This review discusses the known and emerging functions of FGF23, its regulation in response to systemic and local signals, as well as the implications of FGF23 in different pathological and physiological contexts.

Ion microscopic imaging of calcium during 1,25-dihydroxyvitamin D-mediated intestinal absorption

1996 ◽  
Vol 106 (2) ◽  
pp. 215-222 ◽  
Author(s):  
Curtis S. Fullmer ◽  
Subhash Chandra ◽  
Christina A. Smith ◽  
George H. Morrison ◽  
Robert H. Wasserman
Keyword(s):  
Intestinal Absorption ◽  
Microscopic Imaging ◽  
Dihydroxyvitamin D ◽  
1,25 Dihydroxyvitamin D

Ion microscopic imaging of calcium during 1,25-dihydroxyvitamin D-mediated intestinal absorption

1996 ◽  
Vol 106 (2) ◽  
pp. 215-222 ◽  
Author(s):  
C. S. Fullmer ◽  
Subhash Chandra ◽  
Christina A. Smith ◽  
George H. Morrison ◽  
Robert H. Wasserman
Keyword(s):  
Intestinal Absorption ◽  
Microscopic Imaging ◽  
Dihydroxyvitamin D ◽  
1,25 Dihydroxyvitamin D

Effects of Retinoic Acid and 1,25-Dihydroxyvitamin D3 on IFN-gamma Secretion by Mononuclear Leukocytes from Nulliparous and Postparturient Dairy Cattle

2000 ◽  
Vol 70 (3) ◽  
pp. 92-101 ◽  
Author(s):  
Burim Ametaj ◽  
Brian Nonnecke ◽  
Ronald Horst ◽  
Donald Beitz
Keyword(s):  
Retinoic Acid ◽  
Dairy Cattle ◽  
Dairy Cows ◽  
Dairy Cow ◽  
Pokeweed Mitogen ◽  
Mononuclear Leukocytes ◽  
Combined Effects ◽  
Ifn Gamma ◽  
Dihydroxyvitamin D ◽  
1,25 Dihydroxyvitamin D

Individual and combined effects of several isomers of retinoic acid (RA) and 1,25-dihydroxyvitamin D3 (1,25-(OH)2D3) on interferon-gamma (IFN-gamma) secretion by blood mononuclear leukocytes (MNL) from nulliparous and postparturient Holstein cattle were evaluated in vitro. In the first experiment, effects on incubation period (24 to 72 hours) and time of supplementation (0 to 32 hours) with all-trans, 9-cis, 13-cis-, and 9,13-dicis-RAs (0 to 100 nM) on IFN-gamma secretion by pokeweed mitogen (PWM)-stimulated (0 and 10 mug/ml) MNL from nulliparous cattle were evaluated. In the second experiment, MNL from postparturient cows (bled at 0, 2, 4, and 16 days postpartum) were stimulated with PWM (0 and 10 mug/ml) in the presence of RA isomers (9-cis- or 9,13-dicis-RA; 0 to 100 nM), 1,25-(OH)2D3 (0 to 100 nM), or with combinations of these metabolites. The results show that individual isomers of RA had no effect on IFN-gamma secretion by PWM-stimulated MNL from nulliparous or postparturient cows. Furthermore 1,25-dihydroxyvitamin D3 inhibited IFN-gamma secretion by MNL from nulliparous and postparturient dairy cows; however, the degree of inhibition was greater when 9-cis- and 9,13-dicis-RA were also present in the cultures. Finally mononuclear leukocytes from postparturient dairy cows produced substantially less IFN-gamma than did MNL from nulliparous cattle. It is concluded that retinoic acids individually did not affect the capacity of leukocytes from dairy cattle to secrete IFN-gamma. This result is in marked contrast to studies in monogastric species indicating that RAs inhibit IFN-gamma secretion by peripheral blood T cells. Inhibition of IFN-gamma secretion by 1,25-(OH)2D3 was potentiated by 9-cis- and 9,13-di-cis-retinoics acids, suggesting that an excess of dietary vitamins A and D may compromise further the naturally immunosuppressed postparturient dairy cow. Additional research is necessary to determine if the combined effects of these metabolites on IFN-gamma secretion represent an increased susceptibility of the dairy cow to infectious diseases during the periparturient period. Lower secretion of IFN-gamma by MNL from postpartutient dairy cows, relative to nulliparous cattle, suggests that recently-calved cows are naturally immunosuppressed.

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