Interrelationship between serum concentrations of 1,25-dihydroxyvitamin D, parathyroid hormone and renal haemodynamics after low dose cyclosporin.
It is unclear whether cyclosporin A (CsA) alters the synthesis of 1,25-dihydroxyvitamin D3 [1,25(OH)2D] by the normal human kidney. Serial changes in 1,25(OH)2D, parathyroid hormone (PTH), GFR and renal blood flow were compared in 14 patients with psoriasis who were being treated with less than 5 mg/kg/day of cyclosporin for 3 months. GFR fell significantly although there were no significant changes in serum 1,25(OH)2D, 25-hydroxyvitamin D or PTH. Absolute values for GFR and PTH were negatively correlated (rP = -0.54; p < 0.001) as were the changes in GFR and PTH observed during CsA therapy (rP = -0.73; p < 0.05). The significant fall in serum magnesium was not significantly correlated with changes in PTH. The close relationship between changes in GFR and PTH suggests that a reduction of GFR within the normal range is enough to stimulate production of PTH. CsA does not appear to stimulate the synthesis of 1,25(OH)2D3 in man.
Edwards
B D
BD
Department of Medicine, Manchester Royal Infirmary, UK.
Davies
M
M
Mawer
E B
EB
Chalmers
R J
RJ
Testa
H J
HJ
Ballardie
F W
FW
D000293:Adolescent; D000328:Adult; D000368:Aged; D000469:Alkaline Phosphatase / Q000032:analysis / Q000097:blood; D015415:Biomarkers / Q000032:analysis / Q000097:blood; D001794:Blood Pressure / Q000187:drug effects; D002117:Calcitriol / Q000097:blood*; D016572:Cyclosporine / Q000008:administration & dosage / Q000494:pharmacology*; D005919:Glomerular Filtration Rate / Q000187:drug effects*; D006801:Humans; D008875:Middle Aged; D010281:Parathyroid Hormone / Q000097:blood*; D010865:Pilot Projects; D011565:Psoriasis / Q000188:drug therapy; D012079:Renal Circulation / Q000187:drug effects*
D015415:Biomarkers; D010281:Parathyroid Hormone; D016572:Cyclosporine; D000469:Alkaline Phosphatase; D002117:Calcitriol