Calcium absorption in corticoid treated subjects effects of a single oral dose of calcitriol.
We compared the fractional absorption of calcium (FACa, 6 h, % TD) and the radiocalcium transit (% TD per min) in seven glucocorticoid-treated patients (10-25 mg prednisolone per day) and in seven normal subjects, in the basal state and 12 h after an oral dose of synthetic 1,25-(OH)2D (3 micrograms). In the basal state, the radiocalcium transit was significantly decreased (P less than 0.02) at 15 min in patients treated with prednisolone, but FACa at 6 h was not significantly decreased (51 +/- 5 vs. 60 +/- 5% TD). 12 h after an oral dose of 1,25-(OH)2D which resulted in supraphysiologic plasma levels, FACa increased significantly (P less than 0.02) in both groups but the peak absorption rate of Ca remained lower in the corticoid-treated patients than in controls (P less than 0.02). The results suggest that glucocorticoids decrease the 1,25-(OH)2D-dependent transport of calcium across the proximal small intestine.
D000368:Aged; D002117:Calcitriol / Q000494:pharmacology*; D002118:Calcium / Q000378:metabolism*; D005260:Female; D006801:Humans; D007408:Intestinal Absorption / Q000187:drug effects*; D007700:Kinetics; D008297:Male; D008875:Middle Aged; D011239:Prednisolone / Q000009:adverse effects*
D011239:Prednisolone; D002117:Calcitriol; D002118:Calcium