THE INTERRELATION OF THE SURVIVING HEART AND PANCREAS OF THE DOG IN SUGAR METABOLISM : SECOND PAPER

When the pancreas of a dog is perfused aseptically with a Locke's solution containing dextrose in physiological concentrations, the optical rotation of the perfusate is diminished, but its reducing power is unaltered. This change also occurs if dextrose is added to a sugarfree pancreatic perfusate and the mixture incubated. These perfusates yield osazones with lower melting points than glucosazone, but when the perfusates are hydrolyzed with weak acid their optical, rotations and the melting points of their osazones are increased. These changes do not occur with levulose, or with an extract of the pancreas and dextrose. When the heart, spleen, or kidneys are perfused with dextrose solutions hydrolysis of the perfusates does not increase their optical rotation or power of reduction. When a pancreatic perfusate containing dextrose is circulated through a living heart not only do the above changes take place but, in addition, the reducing properties of the perfusate are altered. Hydrolysis of such a perfusate increases its reducing power, its optical rotation, and the melting point of its osazone. A heart does not cause this effect either alone or when perfused together with the spleen or kidneys. Levulose perfused through the heart and pancreas is unchanged. These phenomena are believed to be due to an enzyme or enzymes obtained from the perfused pancreas. The changes in optical rotation, in reduction, and in the osazones are accounted for by different degrees of dextrose condensation. While the living heart can destroy both dextrose and levulose to some extent, the experimental results suggest that the enzyme or enzymes derived from the perfused pancreas have a specific action on dextrose and are responsible for certain essential steps by which dextrose is prepared for normal utilization.