Role of the liver in calorigenic action of epinephrine and norepinephrine

¹ Department of Physiology, University of Buffalo School of Medicine, Buffalo, New York

Intravenous infusion of epinephrine and norepinephrine into eviscerated cats at rates of 4 µg/kg/min for 5 min results in an increase in oxygen consumption to an average 121% and 123% of control, respectively, with return to control level in the 15-min period after infusion. A similar response is obtained in normal cats during epinephrine infusion, but only in this group is a secondary or delayed rise to an average 110% of control noted in the 15-min period after infusion. It is suggested that the calorigenic action of epinephrine might be separated into an immediate effect occurring during intravenous infusion, independent of the presence of the liver, and a delayed or secondary effect occurring after infusion, requiring the presence of the liver. Both drugs change lung volume and thus introduce artifacts that interfere with measurement of oxygen consumption by conventional methods. This is overcome by use of a thermostat-controlled compensating body chamber which frees the oxygen consumption record from any dependence on lung volume.