Effect of vitamin D on the intestinal absorption of 203Pb and 47Ca in chicks
The transfer of 203Pb and/or 47Ca across the intestinal epithelium of the chick was investigated, with emphasis given to the functional role of cholecalciferol (vitamin D-3). 203Pb, after introduction in the intestinal lumen, is rapidly accumulated by the intestinal tissue, and only a fraction of 203Pb is translocated parenterally (absorbed). Cholecalciferol did not significantly affect the accumulation of 203Pb by intestinal tissue but did accelerate 203Pb movement across the basal-lateral membrane. In contrast, cholecalciferol both decreased 47Ca tissue levels and increased 47Ca absorption. In rachitic chicks, the rate of absorption of 203Pb was greater in the distal than in the proximal segments of the intestine; after cholecalciferol repletion, the degree of absorption in al segments was similar, indicting the order of cholecalciferol effectiveness as duodenum greater than or equal to jejunum greater than ileum. An acute dose of 1,25(OH)2D3 to rachitic chicks also enhanced both 203Pb and 47Ca absorption, but the time course and pattern of absorption of these metal cations differed. The time at which the absorption of 203Pb peaked and returned to base-line occurred sooner than for 47Ca. Also the back-flux (blood leads to intestinal lumen) of 47Ca was enhanced by cholecalciferol, whereas no effect on the back-flux of 203Pb was noted. These studies show that cholecalciferol and 1,25(OH)2D3 affects both the 203Pb and 47Ca absorptive processes, but the nature of these responses are not identical, suggesting differences in the transport path or the macromolecular interactions of these metal ions during the course of absorption, or both.
- Research Organization:
- Department of Physiology, New York State College of Veterinary Medicine, Cornell University, Ithaca
- OSTI ID:
- 5297754
- Journal Information:
- J. Nutr.; (United States), Vol. 112:3
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
CALCIUM 47
INTESTINAL ABSORPTION
CHOLECALCIFEROL
BIOLOGICAL EFFECTS
LEAD 203
CHICKENS
MEMBRANE TRANSPORT
ABSORPTION
ALKALINE EARTH ISOTOPES
ANIMALS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BIRDS
CALCIUM ISOTOPES
DAYS LIVING RADIOISOTOPES
ELECTRON CAPTURE RADIOISOTOPES
EVEN-ODD NUCLEI
FOWL
HEAVY NUCLEI
INTERMEDIATE MASS NUCLEI
ISOMERIC TRANSITION ISOTOPES
ISOTOPES
LEAD ISOTOPES
NUCLEI
RADIOISOTOPES
SECONDS LIVING RADIOISOTOPES
UPTAKE
VERTEBRATES
VITAMIN D
VITAMINS
551001* - Physiological Systems- Tracer Techniques