The in vivo metabolic events which follow the administration of epinephrine, norepinephrine, or isoproterenol were examined in normal, Bordetella pertussisvaccinated, and a and adrenergically blocked mice. The normal hyperglycemic response to epinephrine was suppressed in all experimental groups. The pertussissensitized and ,B-blocked animals produced similar split patterns of altered response not duplicated by the a-blocking compounds. Those catecholamines that normally increase free fatty acids and lactic acid in the circulation failed to do so in the pertussis-sensitized and fl-blocked animals; the inhibition of free fatty acid mobilization was also demonstrated with adipose tissue incubated in vitro. An extract of the pertussis organism added to incubation media prevented the catecholamine-induced free fatty acid response. The epinephrine-stabilizing effect of bovine serum albumin (Cohn-fraction V) was observed. The results of these studies further emphasize a correlation between pertussis-sensitized and fl-adrenergically blocked mice. MATERIALS AND METHODS Mice. Female, CFW, white mice obtained from Carworth Farms were employed in the present study. They were housed in groups not exceeding 50 in number and were allowed food and water ad libitum. At the time of the experiments, the animals weighed between 18 and 20 g. Pertussis vaccine and extract. Fluid vaccine, a suspension of killed B. pertussis organisms, lot BP-0317, was supplied by Eli Lilly & Co., Indianapolis, Ind. This suspension was diluted 1:2 in sterile, nonpyrogenic, physiological saline. To establish the sensitive state, the animals were injected intraperitoneally with 0.5 ml of this suspension and were used in the experiments 5 days later. A soluble extract of pertussis organisms containing the histamine sensitizing factor was kindly furnished by J. Munoz, Public Health Service, Hamilton, Mont. Drugs. The following materials were purchased commercially from Winthrop Laboratories, New York, N.Y.: epinephrine, synthetic, as bitratrate (Suprarenin) containing 1 mg of base per ml, and isoproterenol HCI (Isuprel) containing 0.2 mg of 804