A Flounder Fish Peptide Shows Anti-Hypertensive Effects by Suppressing the Renin-Angiotensin-Aldosterone System and Endothelin-1.

BACKGROUND

Many fishes have been known for their good nutritional effects especially in the cardiovascular aspect. Some specific fish peptides have anti-hypertensive effects.

OBJECTIVE

In the present study, we hypothesized that the hexapeptide (MEVFVP) from flounder fish muscle can be a potent antihypertensive peptide, therefore, decided to perform this experiment.

METHODS

The peptide MEVFVP from flounder fish muscle (40 mg/kg) and vehicle were administered per os to spontaneously hypertensive rats (SHRs) (SHR-M and SHR-C, respectively). Additionally, plasma MEVFVP was measured serially before and after its oral administration to Sprague Dawley rats.

RESULTS

Blood pressures (BPs), especially systolic BP, in SHR rats were decreased around 3-6 hours after MEVFVP administration. Compared with SHR-C rats, endothelin-1 (ET-1) mRNA expression in multiple tissues, and plasma levels of ET-1, angiotensin II, and aldosterone were lower in SHR-M rats, whereas the phosphorylation of AMP-activated protein kinase (AMPK) was increased in the kidney of SHR-M rats. The administered peptide was not detected in rat plasma, while ex vivo incubation of the peptide in rat plasma caused its rapid degradation within minutes.

CONCLUSION

Our results show that the MEVFVP has an antihypertensive effect by regulating renin- angiotensin-aldosterone system, ET-1 and AMPK despite its limited bioavailability.