Calcium uptake by brush-border and basolateral membrane vesicles in chick duodenum

Journal Article · Mon Jan 01 00:00:00 EST 1990 · American Journal of Physiology; (USA)

OSTI ID:7191989

Takito, J; Shinki, T; Sasaki, T; Suda, T ^[1]

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1. Showa Univ., Tokyo (Japan)

Calcium uptake was compared between duodenal brush-border membrane vesicles (BBMV) and basolateral membrane vesicles (BLMV) isolated from vitamin D-deficient chicks and those injected with 625 ng of 1 alpha,25-dihydroxyvitamin D3 (1 alpha,25(OH)2D3). The uptake by BBMV in the 1 alpha,25-(OH)2D3-treated birds attained a maximum (280% of the control) at 12 h and was maintained at an elevated level (210%) at 24 h after the injection of the vitamin. In contrast, ATP-dependent calcium uptake by BLMV reached a maximum (185% of the control) at 6 h and decreased to the control level at 24 h. The kinetic analysis revealed that 1 alpha,25(OH)2D3 increased Vmax values without any changes in apparent Km values in both BBMV and BLMV. The activity of ATP-dependent calcium uptake was localized exclusively in the basolateral membrane, and the activity was inhibited by vanadate (IC50, 1 microM), but not by oligomycin, theophylline, calmodulin, trifluoperazine, or calbindin D28K. These results indicate that calcium transport through both the brush-border and basolateral membranes is involved in the 1 alpha,25(OH)2D3-dependent intestinal calcium absorption. The initiation of calcium absorption by 1 alpha,25(OH)2D3 appears to be due to an increase in the rate of calcium efflux at the basolateral membrane rather than the rate at the brush-border membrane.

• OSTI ID: 7191989
• Journal Information: American Journal of Physiology; (USA), Vol. 258; ISSN 0002-9513
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
CALCIUM
MEMBRANE TRANSPORT
VITAMIN D
NUTRITIONAL DEFICIENCY
ALKALINE PHOSPHATASE
ATP-ASE
BIOCHEMICAL REACTION KINETICS
CALCIUM ISOTOPES
CHICKENS
INTESTINAL ABSORPTION
MUCOUS MEMBRANES
TRACER TECHNIQUES
ABSORPTION
ACID ANHYDRASES
ALKALINE EARTH ISOTOPES
ALKALINE EARTH METALS
ANIMALS
BIRDS
ELEMENTS
ENZYMES
ESTERASES
FOWL
HYDROLASES
ISOTOPE APPLICATIONS
ISOTOPES
KINETICS
MEMBRANES
METALS
PHOSPHATASES
PHOSPHOHYDROLASES
REACTION KINETICS
UPTAKE
VERTEBRATES
VITAMINS
550201* - Biochemistry- Tracer Techniques