Abstract: In order to explore the effect of soybean peptide on angiotensin I-converting enzyme (ACE) activity in spontaneously hypertensive rats, the ACE activities in thoracic aorta, lung, kidney, heart and cerebra tissues as well as serum of spontaneously hypertensive rats administered with soybean peptide for 8 weeks were determined. The results indicated that ACE activities in thoracic aorta, lung, kidney and cerebra tissues as well as serum of spontaneously hypertensive rats administered with soybean peptide were lower than those of rats administered with saline. Soybean peptide inhibited ACE activity in kidney tissue in a concentration-dependent manner, but it did not exhibit an inhibitory effect on ACE activity in heart tissue. These results suggested that soybean peptide revealed a remarkable inhibitory effect on the expression or activation of ACE in lung, kidney and cerebra tissues of spontaneously hypertensive rats. However, its mechanisms and pathways still need to be further studied.

Key words: soybean peptide, spontaneously hypertensive rats, tissue, ACE activity