Rapid effect of prednisolone on serum 1,25-dihydroxycholecalciferol levels in hypercalcemic sarcoidosis

We have studied a hypercalcemic patient with sarcoidosis and advanced renal failure. Bone biopsy and urinary cAMP excretion indicated suppression of parathyroid function. 1,25(OH)2D levels were moderately elevated and dropped to low normal levels during prednisolone treatment. Discontinuation of prednisolone treatment caused deterioration of renal function and hypercalcemia, 1,25(OH)2D serum levels being within the normal range. Our data demonstrate the rapid speed at which prednisolone causes a drop in serum 1,25(OH)2D level. Since hypercalcemia was observed both during periods of hypercalciuria and normal serum 1,25(OH)2D levels, increased sensitivity to active vitamin D seems likely. There was no significant correlation between 25(OH)D, 24,25(OH)2D or 25,26(OH)2D. Furthermore there was no correlation between any of these three metabolites and either 1,25(OH)2D or serum calcium.