Actions of GIP.
Two structurally similar peptides were isolated from a preparation of GIP using an HPLC system. The major peptide corresponds to GIP1-42 and the minor has the sequence GIP3-42. GIP1-42 has both insulinotropic and somatostatinotropic activities, whereas GIP3-42 has only insignificant activity. GIP was also shown to potentiate insulin release initiated by D-glyceraldehyde, L-leucine/L-glutamine and 2-keto-isocaproic acid. No potentiation was observed with 2-ketocaproate. The 4 substrates studied are all metabolized but via different mechanisms.
D000818:Animals; D002851:Chromatography, High Pressure Liquid; D004357:Drug Synergism; D005749:Gastric Inhibitory Polypeptide / Q000302:isolation & purification / Q000494:pharmacology*; D005753:Gastric Mucosa / Q000187:drug effects / Q000378:metabolism; D005768:Gastrointestinal Hormones / Q000494:pharmacology*; D005985:Glyceraldehyde / Q000494:pharmacology; D013006:Growth Hormone / Q000378:metabolism*; D007328:Insulin / Q000378:metabolism*; D000078790:Insulin Secretion; D007651:Keto Acids / Q000494:pharmacology; D008297:Male; D010179:Pancreas / Q000187:drug effects / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains; D013329:Structure-Activity Relationship
D005768:Gastrointestinal Hormones; D007328:Insulin; D007651:Keto Acids; D005985:Glyceraldehyde; D005749:Gastric Inhibitory Polypeptide; C013082:alpha-ketoisocaproic acid; D013006:Growth Hormone