ADRENERGIC REGULATION OF BLOOD-GLUCOSE LEVELS - POSSIBLE INVOLVEMENT OF POSTSYNAPTIC ALPHA-2 TYPE ADRENERGIC-RECEPTORS REGULATING INSULIN RELEASE

  • 1 January 1980
    • journal article
    • research article
    • Vol. 215  (1) , 226-230
Abstract
Phenoxybenzamine and prazosin (10-7 to 10-4 mol/kg i.p.) are ineffective in inhibiting the hyperglycemia induced by .alpha. adrenergic agonists in fed male mice but phentolamine, yohimbine and dihydroergotamine are effective. .alpha.-2 Type adrenergic receptors may be involved in the regulation of the plasma glucose levels. The release of immunoreactive insulin induced by epinephrine was markedly stimulated by phentolamine, yohimbine and dihydroergotamine, but phenoxybenzamine and prazosin had little effect. The ineffectiveness of these 2 compounds to inhibit the hyperglycemia induced by .alpha. adrenergic agonists indicates that the postsynaptic .alpha. adrenergic receptors which suppress the secretion of immunoreactive insulin from B cells of pancreatic islets are not blocked and that the .alpha. adrenergic receptors which control immunoreactive insulin secretion differ from the classical postsynaptic .alpha. adrenergic receptors and more closely resemble presynaptic .alpha.-2 adrenergic receptors.