Adrenergic-induced hyperglycemia in anaesthetized rats: involvement of peripheral alpha 2-adrenoceptors.
The selective alpha 2-adrenoceptor agonist, UK 14.304, induces a time- and dose-dependent hyperglycemic response in the anaesthetized rat. This hyperglycemia seems to be mediated through the pancreas because lesions of the pancreatic beta-cells induced with streptozotocin completely abolished this hyperglycemic response to UK 14.304 while ganglionic blockade by chlorisondamine did not affect the response. The non-selective agonist, adrenaline, induces a similar hyperglycemic response which is antagonized selectivity by the alpha 2-adrenoceptor antagonist, idazoxan. Combined alpha 1- and beta-adrenoceptor blockade resulted in an increase in the alpha 2-adrenoceptor-mediated hyperglycemic response to adrenaline. Since adrenaline is known not to cross the blood-brain barrier it is concluded that alpha 2-adrenoceptor stimulation induces hyperglycemic responses through a peripheral effect that involves postsynaptic alpha 2-adrenoceptors in the pancreatic beta-cell which are linked to the inhibition of insulin release.
Angel
I
I
Department of Biology, Laboratoires d'Etudes et de Recherches Synthélabo (L.E.R.S.), Paris, France.
Langer
S Z
SZ
D000758:Anesthesia; D000818:Animals; D000959:Antihypertensive Agents / Q000494:pharmacology*; D001786:Blood Glucose / Q000378:metabolism*; D000068438:Brimonidine Tartrate; D003921:Diabetes Mellitus, Experimental / Q000097:blood; D004837:Epinephrine / Q000494:pharmacology; D005730:Ganglionic Blockers / Q000494:pharmacology; D008297:Male; D011810:Quinoxalines / Q000494:pharmacology*; D051381:Rats; D011942:Receptors, Adrenergic, alpha / Q000187:drug effects*; D013565:Sympatholytics / Q000494:pharmacology
D000959:Antihypertensive Agents; D001786:Blood Glucose; D005730:Ganglionic Blockers; D011810:Quinoxalines; D011942:Receptors, Adrenergic, alpha; D013565:Sympatholytics; D000068438:Brimonidine Tartrate; D004837:Epinephrine