Radio-immunoassays for glucagon-like peptides 1 and 2 (GLP-1 and GLP-2).
Gene-sequencing studies have shown that the glucagon precursor contains two additional glucagon-like sequences, the so-called glucagon-like peptides 1 and 2 (GLP-1 and GLP-2). We developed radio-immunoassays against synthetic peptides corresponding to these sequences. Antisera were raised in rabbits after carbodiimide conjugation of peptides to BSA. The selected antisera showed neither mutual cross-reactivity nor cross-reacted with any other peptide of the glucagon family. Trypsin digestion experiments showed that both antisera were directed against the C-terminus of the antigen peptides. Labelling was performed with chloramine T, and separation with plasma-coated charcoal. The detection limit was 7 and 25 pmol/l for GLP-1 and GLP-2. Accurate measurement of both peptides in plasma required extraction. Optimum recovery was obtained with ethanol at 75% (final concentration). The concentrations measured in fasting plasma from 10 normal subjects were 107 +/- 7 pmol/l and 151 +/- 14 pmol/l for GLP-1 and GLP-2, respectively. After a mixed meal the concentrations rose slowly for 2 h reaching 145 +/- 13 and 225 +/- 15 pmol/l.
D000818:Animals; D002850:Chromatography, Gel; D052216:Glucagon-Like Peptide 1; D053767:Glucagon-Like Peptide 2; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007106:Immune Sera; D010455:Peptides / Q000097:blood*; D011817:Rabbits; D011863:Radioimmunoassay / Q000379:methods
D053767:Glucagon-Like Peptide 2; D007106:Immune Sera; D010455:Peptides; D052216:Glucagon-Like Peptide 1