Alpha 2-adrenoceptors and the regulation of glucose, insulin and amylin levels in diabetic rats.
The effects of the selective alpha 2-adrenoceptor agonist UK 14.304 on glucose, insulin and amylin levels were examined in neonatal streptozotocin-induced diabetic rats. UK 14.304 (0.03 to 0.3 mg/kg i.p.) induced a dose-dependent reduction of both insulin and amylin levels in normal rats while UK 14.304 at 0.03 mg/kg had already a maximal effect in diabetic rats. Amylin/insulin molar ratios rose after UK 14.304 administration in diabetic rats but remainded constant in normal rats. The alpha 2-adrenoceptor antagonist deriglidole (3 mg/kg i.p.) slightly increased insulin and amylin levels in the two groups of rats but glucose levels were more markedly decreased in diabetic rats. Deriglidole completely antagonized UK 14.304 (0.1 mg/kg i.p.)-induced changes thereby normalizing amylin/insulin molar ratios in diabetic rats. These results suggest that insulin and amylin are both under inhibitory control via alpha 2-adrenoceptor though the responses may be differentially regulated. It is further suggested that diabetes in the neonatal streptozotocin-induced rat model is associated with a hypersensitivity of the pancreas to alpha 2-adrenoceptor stimulation.
D000682:Amyloid / Q000097:blood*; D000818:Animals; D001786:Blood Glucose / Q000032:analysis*; D000068438:Brimonidine Tartrate; D003921:Diabetes Mellitus, Experimental / Q000378:metabolism*; D005260:Female; D007328:Insulin / Q000097:blood*; D058228:Islet Amyloid Polypeptide; D011810:Quinoxalines / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D018341:Receptors, Adrenergic, alpha-2 / Q000502:physiology*; D013311:Streptozocin
D000682:Amyloid; D001786:Blood Glucose; D007328:Insulin; D058228:Islet Amyloid Polypeptide; D011810:Quinoxalines; D018341:Receptors, Adrenergic, alpha-2; D000068438:Brimonidine Tartrate; D013311:Streptozocin