Abstract
Increasing information on the distribution of lactic acid in the body tissues has suggested that it plays a more complex rôle than has generally been suspected. Evidence was produced 1 to show that brain tissue removes lactic acid from the blood under normal conditions and that lactic acid is added to the blood circulating through the brain during impaired oxidations induced experimentally. It is evident that this equilibrium between lactic acid absorption and outward diffusion must play a part in the acid-base balance of the blood as well as in the brain. Under conditions in which lactic acid is produced in excessive amounts, its removal from the blood is a matter of importance. Himwich and his collaborators 2 showed that excess blood lactic acid produced chiefly in muscles is carried to the liver and stored as glycogen to be converted subsequently into glucose. These findings have been confirmed and extended by Cori and Cori. 3 In an effort to find further sources of blood lactic acid or further means of its disposal, a study was made of the lactic acid content of arterial and coronary venous blood of the heart in situ.
Dogs were anesthetized either with morphine and urethane or with Gréhant's mixture of chloroform and alcohol. The chest was opened during constant artificial respiration and a cannula placed in the coronary sinus. Volume flow of coronary blood was recorded in most of the experiments. Simultaneous samples of arterial and coronary venous blood were analyzed for lactic acid, a difference of 3 mg. % or more being considered as of definite physiological significance.
Get full access to this article
View all access options for this article.