COMPARISON OF SANDWICH ENZYME-LINKED IMMUNOADSORBENT ASSAY AND RADIOIMMUNOASSAY FOR DETERMINATION OF EXOGENOUS GLUCAGON-LIKE PEPTIDE-1(7-36)AMIDE IN PLASMA
L. Pridal et al., COMPARISON OF SANDWICH ENZYME-LINKED IMMUNOADSORBENT ASSAY AND RADIOIMMUNOASSAY FOR DETERMINATION OF EXOGENOUS GLUCAGON-LIKE PEPTIDE-1(7-36)AMIDE IN PLASMA, Journal of pharmaceutical and biomedical analysis, 13(7), 1995, pp. 841-850
A sensitive sandwich enzyme-linked immunoadsorbent assay (ELISA) for d
etermination of exogenous glucagon-like peptide-1(7-36)amide (GLP-1(7-
36)amide) in plasma samples from pharmacokinetic studies is described.
The assay employs an N-terminally directed antibody and a C-terminall
y directed antibody. The ELISA has a working range from 10 to 500 pmol
l(-1), and can be applied to plasma samples from humans, dogs, pigs,
minipigs, cats, rabbits, and rats. The assay was compared to a validat
ed radioimmunoassay (RIA), employing an antibody directed against the
mid-region of GLP-1. After s.c. administration of GLP-1(7-36)amide, th
e plasma immunoreactivity of GLP-1 (P-GLP-1-IR) measured by ELISA was
markedly lower than P-GLP-1-IR measured by RIA. After HPLC fractionati
on of plasma samples with subsequent RIA and ELISA analyses of the fra
ctions, this difference was shown to be due to cross reaction with bio
logically inactive fragments of GLP-1(7-36)amide in the RIA but not in
the ELISA.