Selective alpha 2-adrenoceptor blockade does not enhance glucose-evoked insulin release.
An investigation has been made of the effects of the selective alpha 2-adrenoceptor antagonist, idazoxan, on the plasma immunoreactive insulin and glucose responses following a glucose stimulus in conscious euglycaemic rats. UK 14304 (100 micrograms/kg), a selective alpha 2-adrenoceptor agonist, reduced the insulin response and potentiated the hyperglycaemia elicited by an intra-arterial glucose load (0.25 g/kg), thereby confirming previous findings that alpha 2-adrenoceptors can influence pancreatic insulin secretion and glycaemia. The effects of UK 14304 were totally abolished by idazoxan (1.0 mg/kg), indicating that idazoxan, at the dose studied, effectively antagonized alpha 2-adrenoceptor-mediated responses. However, idazoxan (1.0 mg/kg) by itself did not significantly affect the plasma glucose and insulin responses to glucose challenge. The data indicate that selective alpha 2-adrenoceptor blockade per se does not potentiate glucose-evoked insulin secretion.
John
G W
GW
Glasgow University Department of Medicine and Therapeutics, Gardiner Institute, Western Infirmary, U.K.
Doxey
J C
JC
Walter
D S
DS
Reid
J L
JL
D000317:Adrenergic alpha-Antagonists / Q000494:pharmacology*; D000818:Animals; D001786:Blood Glucose / Q000378:metabolism; D000068438:Brimonidine Tartrate; D004146:Dioxanes / Q000494:pharmacology; D004347:Drug Interactions; D005947:Glucose / Q000494:pharmacology*; D019329:Idazoxan; D007328:Insulin / Q000378:metabolism*; D008297:Male; D011224:Prazosin / Q000494:pharmacology; D011810:Quinoxalines / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains
D000317:Adrenergic alpha-Antagonists; D001786:Blood Glucose; D004146:Dioxanes; D007328:Insulin; D011810:Quinoxalines; D000068438:Brimonidine Tartrate; D005947:Glucose; D011224:Prazosin; D019329:Idazoxan