Abstract
The antihypertensive effect of peptides (Y-2) derived from sardine, valyl-tyrosine and -mixture (MIX) of four dipeptides having angiotensin converting enzyme inhibitory activity was studied in spontaneously hypertensive rats (SHR). 1) Single oral administration of Y-2, valyl-tyrosine and MIX lowered the systolic blood pressure in SHR, and its minimum effective doses were 10, 1, and 10mg/kg, respectively. These effects lasted for 8h after administration. The hypotensive potency of valyl-tyrosine was greater than those of Y-2 and MIX. Valyl-tyrosine (1 and 10mg/kg) lowered the blood pressure dose-dependently. 2) When 1000, 10, and 10mg of Y-2, valyl-tyrosine and MIX, respectively, were administered orally to the SHR twice a day for 10 consecutive days, any of the regimens decreased systolic blood pressure significantly, and the decrement of systolic blood pressure continued for 5 days thereafter. These results indicate that either Y-2, valyl-tyrosine or MIX can exert a potent and long-lasting antihypertensive effect in SHR.
