title: Radioimmunoassay of gastric inhibitory polypeptide.
abstract: A radioimmunoassay for the measurement of gastric inhibitory polypeptide (GIP) in unextracted plasma in man has been developed using a rabbit antiserum raised against porcine GIP. Porcine GIP was employed also as standard and to produce a 125I-labelled tracer. The assay was able to distinguish 110 pg/ml GIP from zero in plasma samples. Negligible cross-reactivity was demonstrated with cholecystokinin, insulin, pancreatic polypeptide, glucagon, secretin, and vasoactive intestinal polypeptide. The mean overnight fasting plasma GIP level in 28 normal subjects was 203 pg/ml (range: undetectable--420 pg/ml). Plasma GIP levels rose, within 45 minutes of eating a mixed meal, to a mean level of 1573 pg/ml.
mesh_terms: D000818:Animals; D002766:Cholecystokinin / Q000032:analysis; D005749:Gastric Inhibitory Polypeptide / Q000097:blood* / Q000302:isolation & purification; D005768:Gastrointestinal Hormones / Q000097:blood*; D006801:Humans; D011817:Rabbits; D011863:Radioimmunoassay; D012633:Secretin / Q000032:analysis; D013552:Swine
chemical_list: D005768:Gastrointestinal Hormones; D012633:Secretin; D005749:Gastric Inhibitory Polypeptide; D002766:Cholecystokinin