[A determination of anti-insulin receptor antibody in serum--a radioreceptor assay excluded the influence of insulin and anti-insulin antibody].
We studied an anti-insulin receptor antibody (IRAb) assay that excludes the influence of serum insulin and anti-insulin antibody in patients with anti-insulin antibody and normal subjects. The placental membranes strongly bound with 125I-insulin at 4 degrees C. The insulin specificity of the radioreceptor assay was confirmed by adding excess non-labeled insulin and other human hormones to the assay system. The strong correlation between the receptor binding reactivity (%) and the anti-insulin antibody levels was noted in the conventional direct IRAb assay (r = -0.95), but not in the present IRAb assay (r = 0.46) in 10 clinical samples. The placental membranes were stable as the target insulin receptor for IRAb assay at -80 degrees C for at least 4 months. A significant difference in IRAb levels was found between 10 patients with positive anti-insulin antibody and 20 normal controls (p less than 0.01, student t test). The coexistence of insulin and anti-insulin antibody were removed by absorbance to silicagel and by utilizing the two-step (indirect) assay, respectively. IRAb assay without the influence of serum cofactors showed excellent reproducibilities (CV 4.4% (N = 5) and 12.5% (N = 5) in within and between assay variations, respectively).
SRL, Inc., Hachioji Laboratory.
K
K
Satoh
R
R
Kawaguchi
M
M
Yonezawa
K
K
Kubono
K
K
Hikiji
T
T
Ishigami
Y
Y
Tsukada
M
M
Takahashi
D001323:Autoantibodies / Q000032:analysis*; D005260:Female; D006801:Humans; D007328:Insulin / Q000097:blood*; D007330:Insulin Antibodies / Q000032:analysis*; D008297:Male; D011869:Radioligand Assay / Q000379:methods; D011972:Receptor, Insulin / Q000276:immunology*
D001323:Autoantibodies; D007328:Insulin; D007330:Insulin Antibodies; D011972:Receptor, Insulin