Time and dose dependencies for priming effect of glucose on insulin secretion.
Short-term exposure to glucose increases insulin secretion during subsequent stimulation. This priming effect of glucose was further investigated in the perfused rat pancreas. A 5-min pulse of 27.7 mM glucose enhanced the response to a second pulse of the sugar after a 5- or 30-min period of 3.9 mM glucose. With a 10-min pulse of 27.7 mM glucose, the priming effect tended to persist also after a 60-min but not after a 90-min rest period. The priming effects of glucose were also evaluated from enhancement of stimulation 15 min later with 3-isobutyl-l-methylxanthine (IBMX). A 10-min pulse of 8.3 and 27.7, but not 5.6 mM glucose enhanced IBMX-induced insulin secretion. Cycloheximide did not abolish the priming effect of glucose on IBMX-induced insulin secretion. Conclusions are 1) priming is rapidly induced; 2) it persists longer than the time of induction; 3) threshold concentrations of glucose that induce priming are similar to those that initiate insulin secretions; and 4) mechanisms causing priming may not involve protein synthesis.
D015056:1-Methyl-3-isobutylxanthine / Q000494:pharmacology; D000818:Animals; D001786:Blood Glucose / Q000502:physiology*; D003513:Cycloheximide / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D005947:Glucose / Q000494:pharmacology; D007328:Insulin / Q000097:blood*; D007515:Islets of Langerhans / Q000187:drug effects; D008297:Male; D051381:Rats; D012636:Secretory Rate / Q000187:drug effects
D001786:Blood Glucose; D007328:Insulin; D003513:Cycloheximide; D005947:Glucose; D015056:1-Methyl-3-isobutylxanthine