Response of renal transplanted patients to oral calcium load.
In a previous study we demonstrated that cyclosporin-treated renal transplanted patients have a reduced 1,25(OH)2D3 synthesis in comparison with azathioprine-treated transplanted patients. To assess the impact of this defect on intestinal calcium transport we compared the plasma calcium variation and the urinary calcium excretion in 14 cyclosporin-treated and in 12 azathioprine-treated patients, in fasting conditions and 4 hours after an oral calcium load (1 g). In ten cyclosporin patients we also correlated cyclosporin plasma values with plasma 1,25(OH)2D3 values before and after a 25(OH)D3 oral load. After the oral calcium load, plasma and urinary calcium increased significantly in the azathioprine group, while remaining unchanged in the cyclosporin group. A negative correlation between plasma concentrations of cyclosporin and the increment in 1,25(OH)2D3 after 25(OH)D3 oral load was also observed. Thus, our data suggest that cyclosporin impairs 1-alpha hydroxylase activity and alters the response to an oral calcium load.
Graziani
G
G
Divisione di Nefrologia e Dialisi, Ospedale Maggiore di Milano, Italy.
Castelnovo
C
C
Aroldi
A
A
Adami
S
S
Viganò
E
E
Casati
S
S
De Vecchi
A
A
D000328:Adult; D001379:Azathioprine / Q000009:adverse effects / Q000097:blood / Q000627:therapeutic use; D002112:Calcifediol / Q000097:blood; D002117:Calcitriol / Q000097:blood; D002118:Calcium / Q000097:blood / Q000494:pharmacology* / Q000652:urine; D016572:Cyclosporine / Q000009:adverse effects / Q000097:blood / Q000627:therapeutic use; D004032:Diet; D004039:Diet, Sodium-Restricted; D005260:Female; D006801:Humans; D016030:Kidney Transplantation / Q000502:physiology*; D008297:Male; D014807:Vitamin D / Q000097:blood
D014807:Vitamin D; D016572:Cyclosporine; D002117:Calcitriol; D001379:Azathioprine; D002112:Calcifediol; D002118:Calcium