Ethanol-induced adrenomedullary catecholamine secretion in LS/Ibg and SS/Ibg mice

Ethanol, administered i.p., produced a dose-dependent increase in plasma norepinephrine and epinephrine concentrations in LS/Ibg (LS) but not in SS/Ibg (SS) lines of mice. Ethanol-induced elevations of plasma epinephrine in LS mice were approximately 10-fold greater than those observed in SS mice. Plasma epinephrine and norepinephrine attained peak concentrations at 20-min post-ethanol administration at doses ranging from 2.8 to 4.1 g/kg. Plasma catecholamines remained elevated for approximately 1 hr and returned to basal values 2 hr after ethanol administration. Significant correlations were obtained between blood ethanol (r = 0.99), plasma epinephrine (r = 0.92) and plasma glucose (r = 0.98) as a function of ethanol dose in LS mice. Chlorisondamine (3 mg/kg), a ganglionic blocker, abolished completely the ethanol-induced increase in plasma catecholamines. These results confirm previous suggestions that the response is centrally mediated through an increased sympathetic outflow rather than by a direct effect on the adrenal medulla. The increase in plasma epinephrine and associated hyperglycemia produced by ethanol was not observed with pentobarbital or halothane anesthesia. Ethanol-induced hypothermia was diminished markedly (47%) by an elevated ambient temperature (28 degrees C) without reducing the hyperglycemic response to ethanol. These results suggest that ethanol-induced hypothermia does not mediate ethanol-induced adrenomedullary catecholamine secretion and concomitant hyperglycemia. It is proposed that the differential ethanol-induced secretion of adrenomedullary catecholamines in LS and SS mice is due to differential central nervous system sensitivities to ethanol.