Antihypertensive effects of peptide in sake and its by-products on spontaneously hypertensive rats.

Systolic blood pressure (SBP) decreased significantly when the hydrolysate of sake lee (HSL) and peptide fraction of sake (PFS) were orally administrated to spontaneously hypertensive rats (SHR). SBP of "young" SHR decreased significantly after orally administering Val-Tyr, His-Tyr, Arg-Phe, Val-Trp, and Tyr-Trp that were isolated from PFS and HSL. The hypotensive effect of Val-Tyr and His-Tyr that was observed in "young" SHR disappeared as they got older, but PFS and HSL maintained their antihypertensive effect on "aged" SHR. SHR fed on a diet with HSL replacing half of the protein source for 3 weeks showed a significant decrease in SBP after 10 days of feeding.