Measurement of insulin in human sera using a new RIA kit. 1. Insulin determination in the absence of insulin antibodies--conventional assay and micro modification.
A sensitive and versatile radioimmunoassay (RIA) for insulin was established using human insulin standard, a specific guinea pig anti-insulin antiserum and rabbit anti-guinea pig serum. Radioiodination was performed according to a modified chloramine T method. Tracer preparations were used for as long as 6 weeks after iodination. The standard curve ranges from 0.044 to 1.2 nmol/l. The intra-assay coefficient of variation (CV) was 3-5% and the inter-assay CV was 6-9% in the optimal range between 0.4 and 0.9 nmol/l. The average recovery of human insulin added to plasma or serum samples was 100.2 +/- 2.0% (n = 38) and 100.1 +/- 1.9% (n = 42), respectively. In addition to human insulin, porcine, canine, rabbit and bovine insulin can also be determined but not rat or mouse insulin. The cross-reactivity of the antiserum with porcine proinsulin was found to be 40% on the molar basis. The range of mean fasting plasma insulin concentrations in healthy subjects and under various pathological conditions were estimated.
Besch
W
W
Central Institute of Diabetes Gerhardt Katsch, Karlsburg, GDR.
Woltanski
K P
KP
Keilacker
H
H
Diaz-Alonso
J M
JM
Schulz
B
B
Amendt
P
P
Kohnert
K D
KD
Ziegler
M
M
D006801:Humans; D007328:Insulin / Q000097:blood*; D007330:Insulin Antibodies / Q000032:analysis; D011863:Radioimmunoassay; D011933:Reagent Kits, Diagnostic
D007328:Insulin; D007330:Insulin Antibodies; D011933:Reagent Kits, Diagnostic