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Time course of calcium absorption in humans: evidence for a colonic component
- Source :
- Calcified tissue international. 44(5)
- Publication Year :
- 1989
-
Abstract
- We examined the time course of calcium absorption (CaAbs) in 155 studies, using a double isotope technique. The subjects were 118 healthy peri-menopausal women (mean age 53.3 years), studied as impatients under metabolic balance conditions. We measured the ratio of radiolabeled calcium (oral:IV) in serum and urine for 144 hours after the oral dose, and generated a composite CaAbs curve for all 155 studies using normalized data. Although CaAbs was 80.9% complete at 3 hours, it was still only 95.8% complete at 7 hours; the remaining 4.2% was absorbed in a slower late component, and did not reach completion until about 26 hours. The rapid initial component probably represents mainly small intestinal absorption and the late component, colonic. At the dietary intakes of our subjects, we estimate the size of the late component at about 6.8 mg/day. For fully accurate measurements of CaAbs, it is necessary to allow for this small late component.
- Subjects :
- Calcium metabolism
Oral dose
medicine.medical_specialty
Time Factors
Component (thermodynamics)
Chemistry
Colon
Endocrinology, Diabetes and Metabolism
Calcium Radioisotopes
Physiology
chemistry.chemical_element
Mean age
Urine
Calcium
Middle Aged
Intestinal absorption
Surgery
Calcium, Dietary
Endocrinology
Intestinal Absorption
Time course
medicine
Humans
Orthopedics and Sports Medicine
Female
Subjects
Details
- ISSN :
- 0171967X
- Volume :
- 44
- Issue :
- 5
- Database :
- OpenAIRE
- Journal :
- Calcified tissue international
- Accession number :
- edsair.doi.dedup.....655c758ec43423bb2d3ec18b97a3f654