Vitamin D Metabolism in Patients Intoxicated with Ergocalciferol

Abstract

Vitamin D metabolites were measured on admission in eight patients intoxicated with ergocalciferol (serum calcium 3.01-4.05 mmol/l) and also during the subsequent 2 months in six of the eight. Serum concentrations of 25-hydroxyergocalciferol, on admission, were grossly elevated in all patients (range 583-1843 nmol/l). Serum calcium concentration was related significantly only to the concentration of 25-hydroxyergocalciferol (P = 0.003). Concentrations of 25-hydroxyergocalciferol in serum were significantly related to those of calciferol (P = 0.004). Elevated initial concentrations of 1,25-dihydroxycalciferol, mainly as 1,25-dihydroxyergocalciferol, were found in seven of the eight patients (range 179-313 pmol/l). It is suggested that the hypercalcaemia in these patients may be explained by the action of 25-hydroxyergocalciferol at high concentration in competing for 1,25-dihydroxycalciferol receptors, thus exerting a biological effect per se, and also by increasing the synthesis of 1,25-dihydroxycalciferol through a mass-action effect on the renal 1 alpha-hydroxylase.

Association between serum vitamin D metabolite levels and disease activity in patients with early inflammatory polyarthritis

“…Vitamin D metabolites were measured by in-house assays as described previously (16)(17)(18). Briefly, serum samples were extracted using acetonitrile and applied to C-18 Silica Sep-Pak columns (Waters, Elstree, UK).…”

Vitamin D supply to the rat fetus and neonate.

“…Female Norwegian hooded rats were housed in the absence of ultraviolet light and fed from weaning on a semisynthetic vitamin D-deficient diet (17). The female offspring of these animals were raised under the same conditions and used for breeding when they weighed -215 g. The plasma of these second-generation, vitamin D-deficient rats contained no detectable 25(OH)D on HPLC (18) and the concentration of 1,25-dihydroxyvitamin D measured by RIA (18) was only [30][31][32][33][34][35][36][37][38][39][40] pg/ml (normal range 78±6 pg/ml).…”

Calbindin-D9K Gene Expression in Rat Chorioallantoic Placenta Is Not Regulated by 1,25-Dihydroxyvitamin D3

“…Plasma 25(OH)D3 and 1,25(OH),D3 concentrations were determined after extraction with acetonitrile and preliminary separation by HPLC. Concentrations of the metabolites were estimated by absorbance at 265 nm on a second HPLC separation for 25(OH)D3 (20) and by radioimmunoassay using a MAb for 1,25(OH),D3 (21).…”