Inhibition of dibutyryl cyclic AMP-induced insulin release by alpha-2 adrenergic stimulation.
Effects of alpha adrenergic agonists and antagonists on dibutyryl cAMP (Bt2cAMP)-induced insulin release were investigated with isolated rat pancreatic islets. Bt2cAMP (4 mM) produced 2-fold stimulation of insulin release in all the concentrations of glucose examined (3.3-16.7 mM). Clonidine but not phenylephrine inhibited the Bt2cAMP-stimulated insulin release in a concentration-dependent manner with approximate EC50 of nanomolar range. Yohimbine but not prazosin antagonized the inhibitory effect of clonidine on the Bt2-cAMP-induced insulin release. These results suggest that alpha-2 adrenergic mechanisms are involved in a step distal to cAMP generation.
D000316:Adrenergic alpha-Agonists / Q000494:pharmacology*; D000317:Adrenergic alpha-Antagonists / Q000494:pharmacology*; D000818:Animals; D003994:Bucladesine / Q000037:antagonists & inhibitors / Q000494:pharmacology; D007328:Insulin / Q000378:metabolism*; D000078790:Insulin Secretion; D007515:Islets of Langerhans / Q000378:metabolism*; D008297:Male; D051381:Rats; D011942:Receptors, Adrenergic, alpha / Q000187:drug effects; D012636:Secretory Rate / Q000187:drug effects
D000316:Adrenergic alpha-Agonists; D000317:Adrenergic alpha-Antagonists; D007328:Insulin; D011942:Receptors, Adrenergic, alpha; D003994:Bucladesine