Effect of 1,25-dihydroxyvitamin D3 on calcium and magnesium absorption in the healthy human jejunum and ileum

Guenter J. Krejs, Michael J. Nicar, Joseph E. Zerwekh, Daniel A. Norman, Mary G. Kane, Charles Y C Pak

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46 Scopus citations

Abstract

In calcium deficiency states such as chronic renal failure, 1,25-dihydroxyvitamin D3 increases calcium and magnesium absorption toward normal levels. In the present study, the ability of exogenous 1,25-dihydroxyvitamin D3 to increase calcium and magnesium absorption above normal rates in healthy subjects was investigated. Steady-state perfusion studies were performed in 30 cm segments of jejunum and ileum before and after one week of 1,25-dihydroxyvitamin D3 administration (2 μg per day, 10 subjects). Serum 1,25-dihydroxyvitamin D concentration increased from 25.8 ± 2.5 pg/ml to 56.4 ± 6.6 (mean ± SEM, p < 0.05). In the basal state, calcium absorption was significantly higher in the jejunum than in the ileum. Vitamin D administration resulted in a significant increase in calcium absorption which was quantitatively similar in both the jejunum and ileum. The changes in net movement were due to an increase in lumen-to-plasma flux of calcium; the plasma-to-lumen flux remained unchanged. Jejunal magnesium absorption also was enhanced by 1,25-dihydroxyvitamin D3. These studies demonstrate that in healthy persons, exogenous 1,25-dihydroxyvitamin D3 increases calcium absorption in both the jejunum and the ileum, and increases magnesium absorption in the jejunum.

Original languageEnglish (US)
Pages (from-to)973-976
Number of pages4
JournalThe American Journal of Medicine
Volume75
Issue number6
DOIs
StatePublished - Dec 1983

ASJC Scopus subject areas

  • Medicine(all)

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