Effect of γ-aminobutyric acid-enriched tempeh-like fermented soybean (GABA-tempeh) on the blood pressure of spontaneously hypertensive rats

GABA-enriched tempeh-like fermented soybean (GABA-tempeh) was supplemented to the AIN-76 diet and fed for 2 months to spontaneously hypertensive rats (SHRs), an animal model of spontaneously developed hypertension, to compare the antihypertensive activity with that of authentic GABA. The elevation of systolic blood pressure in SHRs was significantly retarded in the GABA-tempeh group as well as that with authentic GABA when compared with the controls, and the effect lasted for two months of the feeding period. The blood urea nitrogen level tended to be higher. in the control group than in the GABA-supplemented groups. On the other hand, no effect was apparent on the plasma levels of cholesterol, triacylglycerol and glucose, or on the urinary excretion of Na and K.