Phosphate-independent, carrier-mediated active transport of calcium by rat intestine

Walling, Marlin W.; Rothman, Stephen

doi:10.1152/ajplegacy.1969.217.4.1144

Cited by 94 publications

(42 citation statements)

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“…Our data show that 1,25-(OH)2D3 induces a saturable active absorptive process for Ca in colon with an apparent Km of 0.9 mM, which is similar to those estimated for rat duodenum, (7) and ileum (15). This suggests that the colonic cells which transport Ca may have the same 1,25(OH)2D3-stimulated process as their small intestinal counterparts and provides a persuasive argument for the existence of Pi-independent Ca-transporting cells in the small intestine (7,16 (19,20). The clear dissociation between Ca and Pi transport activities in colon suggests that this intestinal segment may provide a useful model system for studying molecular events, e.g., induction of proteins and enzymes, related to Ca but not Pi transport activities; whereas the apparent influence of 1,25(OH)2D3 on the Ca secretory process may furnish further insight into the mechanism of action of vitamin D.…”

Section: Methodssupporting

confidence: 85%

“…tion of both Ca and Pi (1). Our data show that 1,25-(OH)2D3 induces a saturable active absorptive process for Ca in colon with an apparent Km of 0.9 mM, which is similar to those estimated for rat duodenum, (7) and ileum (15). This suggests that the colonic cells which transport Ca may have the same 1,25(OH)2D3-stimulated process as their small intestinal counterparts and provides a persuasive argument for the existence of Pi-independent Ca-transporting cells in the small intestine (7,16 (19,20).…”

Section: Methodssupporting

confidence: 82%

“…Transmural Ca and Pi fluxes were studied in vitro employing the modified Ussing technique described in detail in prior publications (1,(7)(8)(9) (9), and ion fluxes were calculated as described (10). The transmural potential difference was abolished using automatic voltage clamps (Netronics, Inc., Hudson, Mass.)…”

Section: Methodsmentioning

confidence: 99%

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Calcium and Inorganic Phosphate Transport in Rat Colon

Lee¹,

Walling²,

Gafter³

et al. 1980

J. Clin. Invest.

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Section: Methodssupporting

confidence: 85%

Section: Methodssupporting

confidence: 82%

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Calcium and Inorganic Phosphate Transport in Rat Colon

Lee¹,

Walling²,

Gafter³

et al. 1980

J. Clin. Invest.

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“…These studies are the first to demonstrate the maturational aspects of calcium entry at the brush border level and are consistent with our previous kinetic studies utilizing whole tissue. Intestinal calcium transport in the rat has been studied by in vivo perfusion techniques (I), everted gut sacs (2), and Ussing chambers (3). These studies provided the overall picture of calcium absorption and has shown that calcium transport occurs by mediated and nonmediated processes (1-3).…”

mentioning

confidence: 99%

Developmental Maturation of Calcium Transport by Rat Brush Border Membrane Vesicles

Arab

1987

Pediatr Res

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ABSTRACT. The developmental aspects of calcium transport across the intestinal brush membrane vesicles was studied utilizing a millipore filtration technique. Calcium transport represented uptake into the intra vesicular space as evidenced by osmolality studies, calcium release by the calcium ionophore A23187, and temperature dependency. Calcium transport in both suckling and adolescent rats appears to occur by a saturable mechanism. Calcium uptake was similar in the presence of sodium and potassium gradients, but decreased in the presence of choline gradient. The imposition of negative membrane potential did not enhance calcium uptake compared to voltage clamp conditions indicating an electroneutral process. The initial rate of calcium uptake was linear up to 15 s. Kinetic analysis of calcium uptake at 7 s showed lower Vmax and lower Km in suckling rats compared to adolescent rats. These studies are the first to demonstrate the maturational aspects of calcium entry at the brush border level and are consistent with our previous kinetic studies utilizing whole tissue. (Pediatr Res 22: 173-176, 1987) Abbreviation BBMV, brush border membrane vesicles Intestinal calcium transport in the rat has been studied by in vivo perfusion techniques (I), everted gut sacs (2), and Ussing chambers (3). These studies provided the overall picture of calcium absorption and has shown that calcium transport occurs by mediated and nonmediated processes (1-3). The mediated process is regulated by 1-25(OHh vitamin D3 the most active polar metabolite of vitamin D (4). The nonmediated process occurs mainly through the paracellular pathway (5). Studies on the developmental aspects of calcium transport using everted gut sacs has shown that the contribution of the non mediated process to the total process of transport declines with age while the mediated component increases (2). The permeability coefficient of calcium in everted gut sacs was higher in suckling rats compared to adolescent rats. Recently studies using isolated membrane vesicles have provided insight into the process of uptake and exit separately. These membrane vesicles otTerthe advantage of setting the experimental conditions at will, i.e. defining the composition of the media at both sides of the membrane without interference with cell metabolism (6). We have recently validated the use of brush border membrane vesicles for the study of developmental aspects of transport (7,8).Using a well-validated technique, we designed the current studies to examine the developmental aspects of calcium transport across the brush border membrane vesicles of the rat intestine. BBMV. Sprague-Dawley rats of varying ages (suckling 14-15 days old and adolescent 42-44 days old) were supplied by Sasco Industries (Omaha, NE) suckling rats were purchased with their mothers. Adolescent rats were shipped directly from the supplier. The animals were housed in the animal care facility. Suckling rats were allowed to suckle freely mother's milk, while adolescent rats were fed standard rat chow (Teklad ...

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“…All the previous work had been carried out with I mM-Ca2+ in the medium, and it may be that this is not the optimal concentration to see a vitamin Dmediated effect on surface binding. Martin & deLuca (1969) estimated the K., of mucosal influx, assuming simple Michaelis-Menten kinetics for the overall process, to be about 2mM, and an estimate of 1.25 mm was arrived at by studies on transfer across whole intestine (Walling & Rothman, 1969), but the binding affinity of calcium-binding protein for Ca2+ has been quoted as 2.6 x105M- (Wasserman et al, 1968). We therefore measured the min uptakes of Ca2+ by intestines taken from vitamin D-depleted and -repleted rats, using media containing Ca2+ ranging in concentration from 0.04 to 9mM.…”

mentioning

confidence: 99%

Influence of cholecalciferol (vitamin D3) on the initial kinetics of the uptake of calcium ions by rat small-intestinal mucosa (Short Communication)

O’Donnell

Smith

1973

Biochemical Journal

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The uptake of Ca2+ by isolated small-intestinal mucosa from vitamin D-depleted and -repleted rats was analysed for the effects of vitamin D on initial kinetics. The rapid association of Ca2+ with the tissue, which is complete within 1min, was unaffected by the vitamin, whereas the subsequent, linear, uptake was significantly increased. Neither the tissue space accessible to inulin nor the permeability to thiourea was influenced by vitamin D treatment.

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Phosphate-independent, carrier-mediated active transport of calcium by rat intestine

Cited by 94 publications

References 0 publications

Calcium and Inorganic Phosphate Transport in Rat Colon

Calcium and Inorganic Phosphate Transport in Rat Colon

Developmental Maturation of Calcium Transport by Rat Brush Border Membrane Vesicles

Influence of cholecalciferol (vitamin D3) on the initial kinetics of the uptake of calcium ions by rat small-intestinal mucosa (Short Communication)

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