EFFECT OF PHENYLARSINE OXIDE ON HEPATIC ALPHA(1)-ADRENOCEPTOR RESPONSIVENESS - DISSOCIATION BETWEEN IONOTROPIC AND METABOLIC RESPONSES

The present studies analyze the effect of the tervalent arsenical comp ound phenylarsine oxide (PAO) on hepatic response to oil adrenorecepto r stimulation. PAO, while not significantly altering the rate of glyco gen breakdown, was found to inhibit many characteristic alpha(1)-adren oreceptor mediated responses including H+ and Ca2+ release, increased energy production, and vascular smooth muscle contraction. PAO inhibit ed basal gluconeogenesis but failed to inhibit the alpha(1) agonist in duced stimulation of glucose production. These data suggest that alpha (1)-adrenoreceptor mediated stimulation of metabolism and rates of ion flux across the plasma membrane are separate processes and that excha nge in ion homeostasis is not essential to elicit the receptor-mediate d metabolic responses. The selective effect of PAO offers an interesti ng tool for studying the alpha(1)-adrenoreceptor signaling mechanisms.