Ether Hyperglycemia

Abstract

Glycosuria following etherization was first observed by Reynoso, while the increase of blood sugar accompanying ether anesthesia was first reported by Seelig. Section of the nerves to the liver does not prevent the hyperglycemia resulting from the administration of ether. If the adrenals are inactivated, however, this rise in blood sugar is in large part prevented, as Keeton and Ross showed. That adrenin rather than the action of sympathetic impulses is the potent factor in liberating sugar from the liver has been shown by Bulatao and Cannon and by Britton. Reid had advanced evidence that the hyperglycemia resulting from etherization is due to secretion of adrenin. But after removal of the adrenal factor ether still produces an increase of blood sugar. The demonstration by Cannon and Bacq, that stimulation of the sympathetic nerves produces sympathin and that sympathin resembles adrenin in action, suggested that the residual hyperglycemia from etherization after adrenal influence had been excluded might result from the action of sympathin. If this idea were correct the level of blood sugar should not rise when ether is administered to completely sympa-thectomized animals. Healthy adult cats were maintained in good condition on an adequate diet and fasted for 24 hours before the experiment. Blood (0.1 cc.) was drawn from an ear vein for sugar determinations, which were made in duplicate by the Folin-Svedberg method. The sugar level was determined before etherization and every 15 minutes thereafter, during the administration of the ether, for one hour. A final analysis was made one hour after cessation of the anesthesia. The ether was administered carefully in order to avoid struggle and to minimize emotional reactions. As soon as relaxation was obtained a tube was inserted between the vocal cords into the trachea, and artificial respiration was started in order to avoid asphyxia. The depth of the anesthesia was regulated so that the corneal reflex was just present. Experiments were performed on normal cats, on cats with the left adrenal denervated, the right removed and the hepatic nerves cut, and on cats completely sympathec-tomized. The completeness of the sympathectomy was assured by noting absence of erection of the hairs on exposure to cold or during emotional excitement. Careful necropsy verified these findings. Summary. The elevation of the blood-sugar level in cats on etherization (Fig. 1A) is considerably reduced by inactivating the adrenals and cutting the liver nerves (Fig. 1B). The residual increase persists in the completely sympathectomized animal (Fig. 1C), and therefore does not result from the production of sympathin. The persistent hyperglycemia does not depend upon direct stimulation of adrenal secretion by ether since it is still present when both adrenals have been removed in the completely sympathectomized cat (Fig. 1E).