Poly‐γ‐glutamate Intake Increases Glutamate and GABA Concentrations of Serum and Brain

Abstract

Poly‐γ‐glutamic acid (γ‐PGA) is a mucilaginous and biodegradable compound produced by Bacillus subtilis from fermented soybeans and is found in Korean traditional soy product, cheongkukjang. This study was carried out to evaluate the effects of γ‐PGA from food source on the neurotransmitter GABA and its metabolic precursor, glutamate concentrations in diet‐induced obese rats. Eight week old Sprague‐Dawley male rats (n=60) were used in this study. Rats were divided into two groups and induced obesity by providing either 10% control fat or 45% high fat diet for 5 weeks. And then, rats were blocked into 6 groups and fed 0.1% γ‐PGA diet for 4 weeks. After sacrifice of the rats, brain and serum GABA and glutamate concentrations were analyzed by High Performance Liquid Chromatography with fluorometric detector. The rats fed the high fat diet significantly increased their body weights. Glutamate and GABA concentrations in the serum and brain were significantly (p<0.05) increased by 0.1% γ‐PGA intake in the control fat diet groups while those were not in high fat groups. The results indicated that γ‐PGA intake increased GABA concentration in the serum and brain. However, the effects were not shown in the obese rats. <This study was supported by 2009 Seoul B & RD program.>