Determinants for serum 1,25-dihydroxycholecalciferol in primary hyperparathyroidism.
Serum levels of 1,25-dihydroxyvitamin D3 (1,25(OH)2D3), 25-hydroxyvitamin D3 (25(OH)D3), C-terminal immunoreactive PTH (iPTH), calcium and phosphate, and endogenous creatinine clearance (Clcr) were measured in 34 patients with primary hyperparathyroidism. Clcr ranged from 13 to 161 ml/min (mean 72). S-iPTH was elevated in 82% of the patients and correlated positively to serum calcium (r = 0.74, P less than 0.001) and inversely to Clcr (r = -0.50, P less than 0.02). S-25(OH)D3 was reduced in 28% of the patients and depended on regular multivitamin supplementation (P less than 0.005). S-1,25(OH)2D3 was increased in 26% of the patients and decreased in 9%. It was positively correlated to S-25(OH)D3 (r = 0.39, P less than 0.05) and Clcr (r = 0.42, P less than 0.02) and inversely to serum levels of calcium (r = -0.39, P less than 0.05), phosphate (r = -0.42, P less than 0.02) and iPTH (r = -0.40, P less than 0.05). Multiple regression analysis revealed a positive correlation to 25(OH)D3 when Clcr was taken into account and to Clcr when S-25(OH)D3 was taken into account. When both variables were considered no significant partial correlations were found between S-1,25(OH)2D3 and serum calcium, phosphate and PTH, respectively. It is concluded that serum levels of 25(OH)D3 and renal function are the main determinants for S-1,25(OH)2D3 in primary hyperparathyroidism.
Mosekilde
L
L
University Department of Endocrinology, Aarhus County Hospital, Denmark.
Charles
P
P
Lindegreen
P
P
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002112:Calcifediol / Q000097:blood; D002117:Calcitriol / Q000097:blood*; D002118:Calcium / Q000097:blood; D003404:Creatinine / Q000097:blood; D005260:Female; D006801:Humans; D006980:Hyperthyroidism / Q000097:blood*; D007677:Kidney Function Tests; D008297:Male; D008875:Middle Aged; D010281:Parathyroid Hormone / Q000097:blood; D010710:Phosphates / Q000097:blood; D011863:Radioimmunoassay
D010281:Parathyroid Hormone; D010710:Phosphates; D003404:Creatinine; D002117:Calcitriol; D002112:Calcifediol; D002118:Calcium