Ion microscopic imaging of calcium transport in the intestinal tissue of vitamin D-deficient and vitamin D-replete chickens: A sup 44 Ca stable isotope study

Journal Article · Wed Aug 01 00:00:00 EDT 1990 · Proceedings of the National Academy of Sciences of the United States of America; (USA)

DOI:https://doi.org/10.1073/pnas.87.15.5715· OSTI ID:6527344

Chandra, S; Fullmer, C S; Smith, C A; Wasserman, R H; Morrison, G H ^[1]

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1. Cornell Univ., Ithaca, NY (USA)

The intestinal absorption of calcium includes at least three definable steps; transfer across the microvillar membrane, movement through the cytosolic compartment, and energy-dependent extrusion into the lamina propria, Tracing the movement of calcium through the epithelium has been hampered by lack of suitable techniques and, in this study, advantage was taken of ion microscopy in conjunction with cryosectioning and use of the stable isotope 44Ca to visualize calcium in transit during the absorptive process. The effect of vitamin D, required for optimal calcium absorption, was investigated. Twenty millimolar 44Ca was injected into the duodenal lumen in situ of vitamin D-deficient and vitamin D-replete chickens. At 2.5, 5.0, and 20.0 min after injection, duodenal tissue was obtained and processed for ion microscopic imaging. At 2.5 min. 44Ca was seen to be concentrated in the region subjacent to the microvillar membrane in tissue from both groups. At 5.0 and 20.0 min, a similar pattern of localization was evident in D-deficient tissues. In D-replete tissues, the distribution of 44Ca became more homogenous, indicating that vitamin D increased the rate of transfer of Ca2+ from the apical to the basolateral membrane, a function previously ascribed to the vitamin D-induced calcium-binding protein (28-kDa calbindin-D). Quantitative aspects of the calcium absorptive process were determined in parallel experiments with the radionuclide 47Ca. Complementary information on the localization of the naturally occurring isotopes of calcium (40Ca) and potassium (39K) is also described.

• OSTI ID: 6527344
• Journal Information: Proceedings of the National Academy of Sciences of the United States of America; (USA), Vol. 87:15; ISSN 0027-8424
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
CALCIUM
INTESTINAL ABSORPTION
VITAMIN D
BIOLOGICAL EFFECTS
CALCIUM 40
CALCIUM 44
CALCIUM 47
CELL MEMBRANES
CHICKENS
MEMBRANE TRANSPORT
METABOLISM
MUSCLES
NUTRITIONAL DEFICIENCY
POTASSIUM 39
TRACER TECHNIQUES
ABSORPTION
ALKALI METAL ISOTOPES
ALKALINE EARTH ISOTOPES
ALKALINE EARTH METALS
ANIMALS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BIRDS
CALCIUM ISOTOPES
CELL CONSTITUENTS
DAYS LIVING RADIOISOTOPES
ELEMENTS
EVEN-EVEN NUCLEI
EVEN-ODD NUCLEI
FOWL
INTERMEDIATE MASS NUCLEI
ISOTOPE APPLICATIONS
ISOTOPES
LIGHT NUCLEI
MEMBRANES
METALS
NUCLEI
ODD-EVEN NUCLEI
POTASSIUM ISOTOPES
RADIOISOTOPES
STABLE ISOTOPES
UPTAKE
VERTEBRATES
VITAMINS
550501* - Metabolism- Tracer Techniques