α-Adrenoceptor-mediated glucose release from perifused catfish hepatocytes

摘要: In fish liver catecholamines bind to beta-adrenoceptors (AR) and increase glucose release via cAMP augmentation. Alpha1-AR have recently been shown mediate IP3 Ca2+ elevation in catfish eel hepatocytes, although their coupling a physiological response has remained doubtful. We perifused isolated hepatocytes Bio-Gel P4 columns with epinephrine the presence of prazosin and/or propranolol, alpha- beta-AR antagonists, respectively. Ten nM stimulated approximately 3-fold, this effect was completely antagonized by simultaneous both blockers. The two AR antagonists separately inhibited about one-third two-third total stimulation, Through alpha-AR occupancy, provoked significant whereas no stimulation detected Ca2+-depleted hepatocytes. Glucose strongly elevated ionomycin dibutyryl cAMP. These results represent first direct evidence that transduction pathway is involved epinephrine-induced from