Etiopathogenesis of UVB stimulated calciuria in chronic gastrointestinal patients with decreased supply of vit. D.

It was stated that in patients with chronic gastrointestinal disorders (CGD) and decreased supply of Vit. D (25/OH/D = 6.8 +/- 3.0 ng/ml) during UVB stimulated skin synthesis of Vit.D the increment of Vit.D and 25-hydroxycholecalciferol (25/OH/D) depends on the starting values of Vit.D and 25/OH/D and is accompanied by significant increment of calciuria (delta mean UCa). Before the irradiation with UVB, mean 1,25/OH/2D in age paired healthy controls (50.66 +/- 12.35 pg/ml) when compared with CGD (47.62 +/- 12.08 pg/ml) and F.1,25/OH/2D in controls (2.02 +/- 0.80) and CGD (2.03 +/- 0.46) did not differ when mean PTH in CGD (135.3 +/- 61.6 pg/ml) was significantly higher in CGD (44.6 +/- 18.54 pg/ml, p less than 0.01) than in control group. During and after UVB irradiation completion of CGD mean 1,25/OH/2D levels (129.0 +/- +31.9 pg/ml) as well as F. 1,25/OH/2D index (5.54 +/- +1.54) were rising with the maximum reached on the 14-th day which was paralleled with a subsequent drop in mean PTH (72.3 +/- 24.42 pg/ml) concentration. The data indicated that UVB stimulated calciuria in CGD patients was correlated with increased synthesis of 1,25/OH/2D and increased F. 1,25/OH/2D index which was accompanied with suppression of mean PTH.