Gastric inhibitory polypeptide and insulin response to increasing doses of oral glucose: dependency on glucose amount and volume of the test drink.
The plasma levels of glucose, immunoreactive insulin (IRI), and immunoreactive GIP (IR-GIP) of eight healthy normal-weight subjects were compared following administration of oral glucose load of 10, 30, 60, 90, and 120 g, each given in a volume of 300 and 600 mL of water. By increasing the glucose load from 30 to 60 g, the integrated glucose response was more than doubled, irrespective of the volume. If more than 60 g glucose was given, the venous blood glucose levels did not significantly increase further. The IRI concentrations peaked between 30 and 40 minutes, irrespective of the size and volume of the glucose load. The peak values were significantly higher if 30, 60, and 90 g glucose was given in 600 mL than in 300 mL water. The integrated IRI output increased gradually if the glucose concentration of the 300 mL load was increased, whereas a maximal IRI response occurred already with 60 g glucose if dissolved in 600 mL water. At identical amounts of glucose (60 g) the integrated IRI response was doubled by increasing the ingested volume of the drink from 300 to 600 mL. Also the peak and integrated IR-GIP response increased in a dose-dependent manner by increasing the size of the glucose load. Larger amounts of glucose mainly prolong the GIP response. Significantly greater amounts of IR-GIP were released with 60 and 90 g glucose when given in 600 mL instead of 300 mL water. The parallel increment of IR-GIP and IRI is compatible with an important role of GIP as an insulinotropic gut factor.(ABSTRACT TRUNCATED AT 250 WORDS)
D000284:Administration, Oral; D000328:Adult; D001786:Blood Glucose; D004305:Dose-Response Relationship, Drug; D005260:Female; D005749:Gastric Inhibitory Polypeptide / Q000097:blood*; D005947:Glucose / Q000008:administration & dosage / Q000494:pharmacology*; D006801:Humans; D007328:Insulin / Q000097:blood*; D008297:Male
D001786:Blood Glucose; D007328:Insulin; D005749:Gastric Inhibitory Polypeptide; D005947:Glucose