A Study on the Intracellular Distribution of Transaminases in the Liver of Mouse

Abstract

Intracellular fractionation was carried out by ultracentrifugal analysis in order to obtain the nuclear, mitochondrial, and supernatant fractions in the liver of mouse. Colorimetric analysis was performed to estimate the distribution patterns of GOT and GPT levels among the fractions. Cortisone was administered intraperitoneally to study the response of the transaminase activities among the three intracellular fractions. Along with study on the influence of cortisone, the effects of dietary protein and fasting were investigated to observe their effects of gluconeogenic activity exerted upon the transaminase activity in the liver of mouse, with the following conclusions. 1. The distributions of GOT and GPT are common to all fractions, the activities in mitochondial fractions being the highest and the nuclear the lowest. 2. GOT level is higher than GPT in every intra-cellular fractions. :l. Cortisone administration causes an increase in the activities of both transaminases in all intracellular fractions, and its magnitude exerted upon GPT being more stronger than GOT. 4. Conditions known to display gluconeogenic action, such as high protein intake and fasting, cause increased levels of GOT and GPT in all intracellular fractions, the magnitude of which is far higher in GPT than in GOT level, as observed with cortisone administration. 5. In the conditions mentioned above, as cortisone administration, increased level of mitochondrial GPT is most pronounced among the three intracellular fractions. A brief discussion was made on the results, especially on the significance of nuclear GOT and GPT as well as variations of these enzymes in the intracellular fractions resulting from gluconeoengesis