正常雌ニワトリの小腸粘膜Cytosolを用いるRadioreceptor Assayによる血清1α, 25-Dihydroxycholecalciferol濃度の測定

抄録

Intestinal mucosa cytosol obtained from 24 to 28 months old hen was applied for the radioreceptor assay, which was developed by Eisman et al^<1)> for the determination of serum 1α, 25-(OH)_2-D_3 using intestinal cytosol obtained from vitamin D deficient chick. Prior to the radioreceptor assay, serum 1α, 25-(OH)_2-D_3 was fractionated and purified essentially according to the method of Eisman et al.^<1)>. 1) The yield of intestinal cytosol protein from one normal hen was six-fold higher than one vitamin D deficient chick. Furthermore, the normal hen is commercially available. 2) The binding affinity and capacity to 1α, 25-(OH)_2-D_3 of the cytosol from normal hen were comparable to those obtained from vitamin D deficient chick. 3) Amounts of 1α, 25-(OH)_2-D_3 measured by the radioreceptor assay using intestinal mucosa cytosol obtained from normal hen and vitamin D deficient chick were well correlated. 4) With this method, the circulating level of 1α, 25-(OH)_2-D_3 was determined to be 41 pg/ml. Patients with renal failure revealed lower concentration of 1α, 25-(OH)_2-D_3. From these results, it was concluded that intestinal mucosa cytosol of normal hen would be a good source of the binding protein for 1α, 25-(OH)_2-D_3 assay.