Enterohepatic physiology of 1,25-dihydroxyvitamin D3

Rajiv Kumar, S. Nagubandi, V. R. Mattox, J. M. Londowski

Research output: Contribution to journalArticle

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Abstract

After intravenous administration of radiolabeled 1,25-dihyroxyvitamin D3 to rats, ~25% of the administered radioactivity appeared in the bile within 24 h. Instillation of the biliary radioactivity into the duodena of other rats was followed by recovery of 15% of the radioactivity in newly secreted bile within 24 h. The process by which products of 1,25-dihydroxyvitamin D3 were excreted in bile was not saturable in the dose range tested (0.275-650 ng). The metabolites of 1,25-dihydroxyvitamin D3 present in bile were found to be much more polar than 1,25-dihydroxyvitamin D3 and were resolved into three fractions on high performance liquid chromatography. 60% of the radioactivity present in bile was retained selectively by DEAE-cellulose; the radioactive material could be eluted from the gel at a low pH or at high salt concentrations. When bile containing the radiolabeled metabolites was incubated at 37°C and pH 5 with β-glucuronidase, there was an increase in the amount of radioactivity comigrating with 1,25-dihydroxyvitamin D3. Treatment of the products of radiolabeled 1,25-dihydroxyvitamin D3 in bile with diazomethane, an agent which converts acids into methyl esters, transformed one of the metabolites into a less polar compound. These results demonstrate that there is a quantitatively important enterohepatic circulation of the products of 1,25-dihydroxyvitamin D3 in the rat.

Original languageEnglish (US)
Pages (from-to)277-284
Number of pages8
JournalJournal of Clinical Investigation
Volume65
Issue number2
StatePublished - 1980

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Calcitriol
Bile
Radioactivity
Diazomethane
Enterohepatic Circulation
DEAE-Cellulose
Glucuronidase
Intravenous Administration
Esters
Salts
Gels
High Pressure Liquid Chromatography
Acids

ASJC Scopus subject areas

  • Medicine(all)

Cite this

Kumar, R., Nagubandi, S., Mattox, V. R., & Londowski, J. M. (1980). Enterohepatic physiology of 1,25-dihydroxyvitamin D3 Journal of Clinical Investigation, 65(2), 277-284.

Enterohepatic physiology of 1,25-dihydroxyvitamin D3 . / Kumar, Rajiv; Nagubandi, S.; Mattox, V. R.; Londowski, J. M.

In: Journal of Clinical Investigation, Vol. 65, No. 2, 1980, p. 277-284.

Research output: Contribution to journalArticle

Kumar, R, Nagubandi, S, Mattox, VR & Londowski, JM 1980, 'Enterohepatic physiology of 1,25-dihydroxyvitamin D3 ', Journal of Clinical Investigation, vol. 65, no. 2, pp. 277-284.
Kumar, Rajiv ; Nagubandi, S. ; Mattox, V. R. ; Londowski, J. M. / Enterohepatic physiology of 1,25-dihydroxyvitamin D3 In: Journal of Clinical Investigation. 1980 ; Vol. 65, No. 2. pp. 277-284.
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