The Effect of Adrenoceptor Blockade on the Release of Gastric Inhibitory Polypeptide after Intraduodenal Glucose in Humans

Abstract

An intravenous infusion of NaCl, NaCl + phentolamine (alpha-adrenoceptor antagonist), or NaCl + propranolol (beta-adrenoceptor antagonist) was given in three series of experiments. After intraduodenal infusion of glucose (82 ml 1.51 M, pH 6.5) the GIP concentration in plasma increased from 42.3 (23.1–62.2) to 225 (107–460) pM during intravenous NaCl, from 35.6 (17.3–38.9) to 251 (127–387) pM during phentolamine, and from 32.5 (5.5–63.4) to 172 (103–405) pM during propranolol administration. The blood glucose response was not different in the three experiments. It is concluded that the non-selective beta-adrenoceptor antagonist propranolol inhibits the release of GIP after intraduodenal administration of glucose.

Key-words:

• Adrenergic blockade
• entero-insular axis
• gastric aspiration
• gastric inhibitory polypeptide (GIP)
• glucose
• humans
• incretin
• insulin
• phentolamine
• propranolol
• radioimmunoassay