scholarly journals Magnesium increases calcium absorption mediated by transcellular transport in small intestine of goats and rats

2004 ◽  
Vol 13 (Suppl. 1) ◽  
pp. 277-280 ◽  
Author(s):  
T. Kozakai ◽  
K. Katoh ◽  
Y. Obara
Keyword(s):  
Small Intestine ◽  
Calcium Absorption ◽  
Transcellular Transport

scholarly journals Effects of Magnesium on Calcium Absorption in the Small Intestine of Goat and Sheep in vitro

2000 ◽  
Vol 71 (2) ◽  
pp. 171-177
Author(s):  
Takaharu KOZAKAI ◽  
Emi KONNO ◽  
Yasuyuki SASAKI ◽  
Kazuo KATOH
Keyword(s):  
Small Intestine ◽  
Calcium Absorption

scholarly journals Intestinal absorption of calcium in rats given diets containing casein or amino acid mixture: the role of casein phosphopeptides

1983 ◽  
Vol 49 (1) ◽  
pp. 67-76 ◽  
Author(s):  
Yeon Sook Lee ◽  
Tadashi Noguchi ◽  
Hiroshi Naito
Keyword(s):  
Small Intestine ◽  
Amino Acid ◽  
Calcium Absorption ◽  
Specific Effect ◽  
Basal Diet ◽  
Amino Acid Mixture ◽  
Acid Mixture ◽  
Distal Small Intestine ◽  
Casein Phosphopeptides

1. In an attempt to investigate calcium absorption in the rat during the postprandial period, with the least alteration of the physical environment, the undisturbed small intestine was ligated in situ 2·5 or 3·0 h after ingestion of a diet containing 200 g casein/kg or an equivalent amino acid mixture, or 925 g casein/kg. Estimation of Ca absorption was made by comparing the amount of soluble 40Ca or 45Ca in the contents of segments from the rats receiving 45Ca by intubation 30 min after withdrawal of food, ligated after a further 30 min, then killed after 0 or 30 min.2. Under conditions such that the estimated amount of a marker, polyethylene glycol, in segments ligated in a defined position was little changed in rats killed 30 min apart, the difference in the amount of soluble 40Ca was much higher in the rats fed on the basal diet containing 200 g casein/kg than in other groups.3. This specific effect on Ca absorption, particularly in the distal portion of the small intestine, could be seen also after 45Ca was directly injected into ligated segments in situ. The amount of 45Ca in the portal blood 15 min after injection of the label was also highest in the rats given the basal diet.4. The results were in agreement with our previous findings that the formation and accumulation of casein phosphopeptides causes an increase in the amount of soluble Ca in the distal small intestine.

Cytoskeletal control of calcium absorption across the rat small intestine

1988 ◽  
Vol 89 (2) ◽  
pp. 197-201 ◽  
Author(s):  
Camille F. Nassar ◽  
Eric W. Khairallah ◽  
Michel G. Nasser ◽  
Zuheir M. Habbal
Keyword(s):  
Small Intestine ◽  
Calcium Absorption ◽  
Rat Small Intestine

scholarly journals The Jejunum and Ileum Mediate Increased Calcium Absorption for Bone Mineralization During Postnatal Development via TRPV6 and Cav1.3 (OR26-07-19)

2019 ◽  
Vol 3 (Supplement_1) ◽  
Author(s):  
Megan Beggs ◽  
Justin Lee ◽  
Kai Busch ◽  
Ahsan Raza ◽  
Henrik Dimke ◽  
...  
Keyword(s):  
Small Intestine ◽  
Research Council ◽  
Epithelial Transport ◽  
Calcium Absorption ◽  
Bone Mineralization ◽  
Plate Thickness ◽  
Calcium Flux ◽  
Calcium Balance ◽  
Engineering Research ◽  
Ussing Chambers

Abstract Objectives Intestinal Ca2+ absorption early in life is vital to achieving optimal bone mineralization. The molecular details of intestinal Ca2+ absorption have been defined in adults, after peak bone mass has been reached, but are largely unexplored during development. We sought to delineate the molecular details of transcellular Ca2+ absorption across the small intestine which facilitate a positive calcium balance during growth. Methods We used wildtype, Cav1.3 knockout and Trpv6 mutant mice. Expression of small intestinal and renal calcium transport genes was assessed using quantitative PCR. Net transcellular 45-calcium flux across intestinal segments was measured in Ussing chambers. Femurs we analyzed using micro-CT and histology. Results Significant TRPV6 mediated Ca2+ flux across the duodenum was absent in pre-weaned (P14) mice but occurred post-weaning. In contrast, we found significant transcellular Ca2+ absorption in the jejunum and ileum at P14 but not 2 months. TRPV6 and Cav1.3 are necessary for this jejunal absorption and Cav1.3 appears to mediate absorption across the ileum although compensation is present in knockout pups. Knockout of Cav1.3 induces a compensatory increase in renal Ca2+ reabsorption in P14 mice although these pups have increased growth plate thickness suggesting delayed bone mineralization. Conclusions This work provides molecular details of how the small intestine facilitates increased demand for Ca2+ early in life to meet the requirements of growth and highlights the complexity of the multiple mechanisms involved in achieving a positive Ca2+ balance. Funding Sources This work is funded by grants from the Women and Children's Health Research Institute, supported by the Stollery Children's Hospital Foundation, and the National Sciences and Engineering Research Council to RTA, who is the Canada Research Chair in Renal Epithelial Transport Physiology. MRB is supported by a Vanier Canada Graduate Scholarship, Alberta Innovates Clinician Fellowship and an NSERC Michael Smith Foreign Study Supplement. H. Dimke is funded by the Danish Medical Research Council. Work at UdS was funded by Deutsche Forschungsgemeinschaft (DFG) by IRTG1830 (to JE, VF), Sonderforschungsbereich (SFB) 894 (to JE, PW) and SFB TRR152 (to VF).

scholarly journals The response of the small intestine to vitamin D. Correlation between calcium-binding-protein production and increased calcium absorption

1974 ◽  
Vol 144 (2) ◽  
pp. 339-346 ◽  
Author(s):  
J S Emtage ◽  
D E M Lawson ◽  
E Kodicek
Keyword(s):  
Vitamin D ◽  
Protein Synthesis ◽  
Small Intestine ◽  
Calcium Binding ◽  
Protein Production ◽  
Calcium Absorption ◽  
Binding Protein ◽  
Calcium Binding Protein ◽  
Intestinal Cell ◽  
Stimulation Of

1. The synthesis of calcium-binding protein, a protein produced in the small intestine in response to vitamin D, was investigated with a view to determining whether calcium-binding-protein production could be correlated with the stimulation of calcium absorption by vitamin D. 2. A radioimmunological assay, which can quantitatively estimate calcium-binding-protein concentrations as low as 1μg/g wet wt., was used to detect the synthesis of soluble calcium-binding protein. 3. When used on intestinal supernatants from chicks dosed with vitamin D, calcium-binding protein was not detectable at 8h but was present after 12h at a concentration of 8.6μg/g wet wt.; in agreement with this an increase in calcium absorption due to vitamin D was detected at 12h but not at 8h. 4. The synthesis of calcium-binding protein was also monitored directly by making use of the ability of the iodinated antiserum to bind specifically to nascent calcium-binding protein chains on intestinal polyribosomes; in this way calcium-binding-protein synthesis could be detected 8h after dosage with vitamin D. Further, the binding reaction indicated a near linear increase in the calcium-binding-protein-synthesizing capacity over a 16h period. 5. From the amount of calcium-binding protein present 12 and 24h after vitamin D administration it is calculated that calcium-binding-protein mRNA is produced at approx. 1mol/min per intestinal cell. 6. It is concluded that the high correlation between the initiation of calcium-binding-protein synthesis and the stimulation of calcium absorption by vitamin D strengthens the proposal that calcium-binding protein plays an important role in calcium transport.

scholarly journals Dietary magnesium increases calcium absorption of ovine small intestine in vivo and in vitro

2002 ◽  
Vol 42 (1) ◽  
pp. 25-33 ◽  
Author(s):  
Takaharu Kozakai ◽  
Norio Uozumi ◽  
Kazuo Katoh ◽  
Yoshiaki Obara
Keyword(s):  
Small Intestine ◽  
Calcium Absorption ◽  
Dietary Magnesium

Calcium Absorption Across Epithelia

2005 ◽  
Vol 85 (1) ◽  
pp. 373-422 ◽  
Author(s):  
Joost G. J. Hoenderop ◽  
Bernd Nilius ◽  
René J. M. Bindels
Keyword(s):  
Small Intestine ◽  
Calcium Absorption ◽  
Continuous Process ◽  
Hormonal Control ◽  
Intestinal Lumen ◽  
Renal Tubules ◽  
Dihydroxyvitamin D ◽  
Rate Limiting Step ◽  
Physiological Relevance ◽  
Organ Systems

Ca2+is an essential ion in all organisms, where it plays a crucial role in processes ranging from the formation and maintenance of the skeleton to the temporal and spatial regulation of neuronal function. The Ca2+balance is maintained by the concerted action of three organ systems, including the gastrointestinal tract, bone, and kidney. An adult ingests on average 1 g Ca2+daily from which 0.35 g is absorbed in the small intestine by a mechanism that is controlled primarily by the calciotropic hormones. To maintain the Ca2+balance, the kidney must excrete the same amount of Ca2+that the small intestine absorbs. This is accomplished by a combination of filtration of Ca2+across the glomeruli and subsequent reabsorption of the filtered Ca2+along the renal tubules. Bone turnover is a continuous process involving both resorption of existing bone and deposition of new bone. The above-mentioned Ca2+fluxes are stimulated by the synergistic actions of active vitamin D (1,25-dihydroxyvitamin D3) and parathyroid hormone. Until recently, the mechanism by which Ca2+enter the absorptive epithelia was unknown. A major breakthrough in completing the molecular details of these pathways was the identification of the epithelial Ca2+channel family consisting of two members: TRPV5 and TRPV6. Functional analysis indicated that these Ca2+channels constitute the rate-limiting step in Ca2+-transporting epithelia. They form the prime target for hormonal control of the active Ca2+flux from the intestinal lumen or urine space to the blood compartment. This review describes the characteristics of epithelial Ca2+transport in general and highlights in particular the distinctive features and the physiological relevance of the new epithelial Ca2+channels accumulating in a comprehensive model for epithelial Ca2+absorption.

scholarly journals Enhanced Calcium Absorption in the Small Intestine by a Phytate-removed Deamidated Soybean Globulin Preparation

2004 ◽  
Vol 68 (7) ◽  
pp. 1598-1600 ◽  
Author(s):  
Hitomi KUMAGAI ◽  
Atsushi KOIZUMI ◽  
Akihiro SUDA ◽  
Noriko SATO ◽  
Hidetoshi SAKURAI ◽  
...  
Keyword(s):  
Small Intestine ◽  
Calcium Absorption

Intestinal phosphate and calcium absorption: joint regulation by thyroid hormones and 1,25-dihydroxyvitamin D3

1986 ◽  
Vol 113 (1) ◽  
pp. 96-103 ◽  
Author(s):  
Heide S. Cross ◽  
Doris Pölzleitner ◽  
Meinrad Peterlik
Keyword(s):  
Small Intestine ◽  
Thyroid Hormones ◽  
Culture Medium ◽  
Calcium Uptake ◽  
Calcium Absorption ◽  
Intact Protein ◽  
Independent Effect ◽  
Dihydroxyvitamin D3 ◽  
Dihydroxyvitamin D ◽  
Hyperthyroid Patients

Abstract. Thyroxine (T4) and triiodothyronine (T3) activate Na+-dependent inorganic phosphate (Pi) transport in organ-cultured embryonic chick small intestine. Induction of transport activity requires intact protein synthesis and can be expressed in enterocytes with varying degrees of differentiation. T3 and T4 exert their effect independent of 1,25-dihydroxyvitamin D3 (1,25(OH)2D3), which is shown to stimulate Pi uptake only in the final stage of embryonic differentiation. At this time point, a potentiating effect of 1,25(OH)2D3 and T4 on Pi transport in cultured jejunum can be demonstrated. Thyroid hormones appear to stimulate Na+ gradient-driven Pi transport without concomitantly raising (Na+-K+)-ATPase activity. T4 has no influence whatsoever on calcium uptake by cultured embryonic small intestine while 1,25(OH)2D3 is effective at all stages of embryonic development investigated (day 15–20). However, when both hormones were present in the culture medium, the effect of 1,25(OH)2D3 on calcium transport is doubled. Our results suggest that the hyperphosphataemia associated with hyperthyroidism is likely to result, at least in part, from the independent effect of thyroid hormones as well as from their potentiation of the 1,25(OH)2D3 action on Na+-dependent intestinal Pi transport. In addition, their permissive effect on 1,25(OH)2D3-induced calcium absorption provides an explanation for unaltered calcium absorption in a number of hyperthyroid patients, although reduced plasma levels of 1,25(OH)2D3 are generally observed in this condition.

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