Many quantitative studies [1-6] have been conducted on the regulatory mechanism of carbohydrate metabolism in various mammalian tissues to date. With regard to glycolysis, in particular, BALDWIN et al.  analyzed enzyme activity in the skeletal muscles of rats during exercise and EDINTON et al.  reported on the quantities of metabolic flux obtained from the metabolic intermediates of glycolysis. JOSEPH and SUBRAHMANYAM  investigated the effects of hormones on carbohydrate metabolism in kidneys. In oral tissues, ROSETT et al.  and SIMPSON  reported enzyme patterns based on an evaluation of enzyme activities associated with glycolysis in gingiva, but they neither distinguished between forward and reverse reactions in the metabolic pathways nor described the methods used to determine enzyme activity in detail. Recently, SIQUARA-DA-ROCHA and NICOLAU  biochemically studied the metabolic activities of porcine dental pulp in different phases of root development. These studies, however, dealt with those enzymes known as metabolic pathway marker enzymes and it is not clear whether or not fluctuations in enzyme activity truly reflected those of the glycolytic and gluconeogenic pathways. Therefore, it is necessary to obtain findings by quantifying the multiple reactions of those enzymes which constitute the metabolic pathways. Consequently, we decided to attempt to quantify the metabolic flow and disclose the regulatory system of carbohydrate metabolism in rabbit masseters. It is the purpose of this paper to reveal the respective enzyme patterns of both the glycolytic and gluconeogenic pathways of rabbit masseters. So, conditions for the measurement of the activity levels of 15 enzymes involved in the glycolytic and/ or glyconeogenic reactions were examined for concentrations of substrates, coenzymes, effectors and auxiliary additions. In addition, the effects of the buffers in the reaction mixture on the specific activity of each enzyme were compared for four different reagents at pH 7.4, to enable the enzyme patterns of both the glycolytic and gluconeogenic pathways to be determined in detail. Finally, the effects of various pH values on the enzyme patterns obtained above were demonstrated with the buffer triethanolamine.