Effects of Ephedrine Upon Blood Lactic Acid and Respiratory Metabolism in Man

The work of Cori and others has definitely established the ability of epinephrine materially to increase the blood lactic acid and blood sugar. Cori and Buchwald 1 produced positive increments in blood lactic acid and sugar in man by continuous intravenous injections of epinephrine. Similar results were obtained in rabbits by subcutaneous injections.

Ephedrine has produced results similar to those given by epinephrine. Himwich, et al., 2 and Nitzescu and Munteanu 3 report work upon amytalized dogs in whom they obtained increases in blood lactic acid after ephedrine injections of 40-50 mg. per kilo. Wilson 4 found a hyperglycemia in dogs and rabbits after the subcutaneous injection of ephedrine in doses of 10-30 mg. per kilo.

The experiments herein reported were performed upon normal students. Ephedrine sulfate was ingested in aqueous solution in doses of 60-90 mg. Venous blood samples were drawn at intervals without stasis and the blood lactic acid determined by the method of Friedemann and Kendall. 5 Blood sugar was determined by Benedict's method. (Table I.)

In view of the calorigenic action of epinephrine and the similar effects of epinephrine and ephedrine upon blood lactic acid, it was decided to study the effect of ephedrine upon the respiratory metabolism. The Benedict-Universal metabolism machine was used in following the changes in oxygen consumption and CO₂ output after ephedrine ingestion. The metabolic rate was determined in the post-absorptive or “basal” state after at least 30 minutes rest in bed. Immediately after the basal run a blood sample was taken for lactic acid analysis. Ephedrine, in doses of 1 mg. per kilo was then ingested and after the effects had become pronounced (as indicated by heart rate) the metabolism was again determined. Positive increments of blood lactic acid and oxygen consumption were obtained.