Kinetics of Intestinal Calcium Transport during Maturation in Rats

Ghishan, Fayez K.; Parker, Paul H.; Nichols, Sharon; Hoyumpa, Anastacio M.

doi:10.1203/00006450-198403000-00003

Cited by 37 publications

(19 citation statements)

References 11 publications

(12 reference statements)

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“…We believe that the reason for failuie to show an effect of vitamin D in vivo in the suckling rat relates to the fact that the majority of calcium is transported by a passive process during this period which may mask any effect on the active process. The large component of passive (nonsaturable) transport has been shown by our laboratory using in vivo (35) and everted gut sacs (36). Therefore, our studies demonstrate for the first time a vitamin D-dependent calcium transport in the Golgi membranes during maturation in the rat.…”

Section: Discussionmentioning

confidence: 59%

Vitamin D-Regulated, ATP-Dependent Calcium Transport by Intestinal Golgi Vesicles during Maturation in the Rat

Arab¹

1989

Pediatr Res

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ABSTRACT. The developmental aspects of Calcium uptake by intestinal Golgi vesicles was determined using highly purified Golgi vesicles from enterocytes of suckling (2 wk old), weanling (3 wk old), and adolescent (6 wk old) rats. Calcium uptake by Golgi vesicles at all age groups represented transport into the intravesicular space as evident by temperature dependency and by calcium ionophore A23187-induced calcium efflux studies. Calcium uptake was driven by ATP at all age groups, however, maximal uptake at 15 min was significantly greater in Golgi vesicles of adolescent rats compared to mean values in Golgi vesicles of suckling rats (p < 0.01). Calcium uptake in the absence of ATP was minimal. The requirement for the adenine base and the hydrolysis of the ,f3-y-phosphodiester was tested by replacement of ATP in the incubation media by CTP and the nonhydrolyzable ATP analogue, adenylyl-(@-y-methylendiphosphonate). Both agents had no stimulatory effect on calcium uptake. Calcium uptake was linear up to 40 s. Kinetic parameters of calcium uptake at free calcium concentrations of 0.04 to 1.0 pM showed a maximal transport capacity of 0.99 + 0.05, 0.55 f 0.04, and 0.29 f 0.03 nmollmg protein115 s for adolescent, weanling, and suckling rats, respectively. Km values were 0.16 f 0.02, 0.12 + 0.03, and 0.07 2 0.02 pM for adolescent, weanling and suckling rats, respectively. Km and V,,, values were significantly different between adolescent and suckling rats (p < 0.01). The calcium regulatory protein calmodulin has no effect on calcium uptake by Golgi vesicles. Vitamin D deficiency in all age groups decreased ATP-dependent calcium uptake. Administration of 1,25-(OH)z vitamin D3 8 h before death enhanced ATP-dependent calcium uptake in all age groups studied. This enhancement was the result of increase in maximal transport capacity of ATP-dependent calcium uptake. This study demonstrates a vitamin D-regulated ATP-driven calcium uptake by intestinal Golgi vesicles at all age groups including the suckling period. This transport system shows developmental patterns in regard to its kinetic parameters. (Pediatr Res 26: 58-62, 1989) Abbreviations 1,25(0H)2 D3, 1,25(OH)2 vitamin D3 AMP-PCP, adenylyl-(@-r-methylendiphosphonate)

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Section: Discussionmentioning

confidence: 59%

Vitamin D-Regulated, ATP-Dependent Calcium Transport by Intestinal Golgi Vesicles during Maturation in the Rat

Arab¹

1989

Pediatr Res

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“…Our laboratory has defined the overall picture of calcium transport during maturation using in vivo perfusion technique and in vitro everted gut sacs (1, 2). These studies have shown that during the suckling period a high affinity, low capacity system for calcium transport exists, which evolve to low affinity, high capacity system during the adolescent period (2). Moreover, a large passive component of transport exists in early life which decreases with increasing age (1,2).…”

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confidence: 99%

Intestinal Maturation: Calcium Transport by Basolateral Membranes

1987

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“…Bronner 1971, Pansu et al 1983b). This period of intestinal maturation and consequent change to active calcium uptake processes [Ghishan et al 1984), coincides with a high requirement for bone calcification in the rat. Calcium uptake by means of active processes diminishes after 42 days of age, with the result that active and passive uptake mechanisms respectively contribute about 50% to total calcium uptake in the adult rat (> 56 days).…”

Section: Discussionmentioning

confidence: 99%

Direct determination of saturable and non-saturable calcium uptake in the developing rat duodenum

et al. 1995

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SummarySignificant changes in saturable and non-saturable intestinal calcium uptake processes occur during development of the rat. A modified 'free floating disc' assay was used to measure total, active and passive duodenal calcium uptake on matching duodenal segments from male Sprague Dawley rats aged 14 to 56 days of age. The results were compared and found to give patterns similar to data published for the in situ ligated loop technique.

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Kinetics of Intestinal Calcium Transport during Maturation in Rats

Cited by 37 publications

References 11 publications

Vitamin D-Regulated, ATP-Dependent Calcium Transport by Intestinal Golgi Vesicles during Maturation in the Rat

Vitamin D-Regulated, ATP-Dependent Calcium Transport by Intestinal Golgi Vesicles during Maturation in the Rat

Intestinal Maturation: Calcium Transport by Basolateral Membranes

Direct determination of saturable and non-saturable calcium uptake in the developing rat duodenum

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