Effect of Muscular Expercise upon the Epinephrine Secretion from the Suprarenal Gland

Dogs, in which the operation area was previously de-afferented, were experimented on. The procedure for collecting the suprarenal vein blood through the lumbar approach was performed, namely with-out their being fastened or without their giving any evidence of pain. The dogs were compelled to run on a paved road or in a revolving wheel. (1) When the animals presented no signs of fatigue or were tired slightly after a run of 360 to 6840 meters, the rate of the epinephrine secretion remained almost unaltered, while in the animals which were much fatigued or exhausted, by running 760 to 2565 meters, the rate was increased from the quiet value of 0.000015-0.000025 mgrm. from one suprarenal capsule per kilo and per minute to 0.00003-0.0001 mgrm.: This peak being noted a few minutes or about a half hour after running. The magnitude of acceleration was thus very small and its duration was short, ad maximum about one hour after run-ning. Whether the epinephrine discharge will be accelerated, though only a little, depends directly upon the condition of the animal, whe-ther exhausted or not, and not directly upon the magnitude of the work. (2) In cases where the animals presented no signs of exhaustion, the blood from the femoral artery, taken soon after cessation of the muscular exertion, exhibited only a slight rise of the glycaemic level or no change. In cases where the animals were exhausted from the muscular effort, the glycaemic percentage showed a tendency to de-crease, though slightly, sooner or later.