Studies in Esterase (Butyric) Activity. II. Esterase Content of Livers of Mice and Its Excretion in Strains Susceptible or Insusceptible to Mammary Cancer

In a previous publication (5) the esterase activity in the serum of a strain of highly inbred laboratory mice that are insusceptible to mammary cancer was shown to be almost double the amount normally found in two susceptible strains. This difference is a resultant of the following three interrelated factors probably working independently of each other: (a) the amount of enzyme elaborated in the liver, (b) its liberation in the circulating blood, and (c) its elimination from the body. It was suggested either that the mice of the insusceptible strain did not produce this enzyme in the liver to the same extent as the susceptible mice or that, even though the mice of these three strains manufactured the enzyme to the same extent, they released it in different proportions in the blood. The following experiments were therefore undertaken to determine the esterase content of the livers and the esterase excretion in the urine and the feces of mice from these three strains.