Inhibition of dog renin activity by pepstatin A

The inhibitory effect of pepstatin A, an isovaleryl pentapeptide isolated from streptmyces, was studied. Pepstatin A inhibited the action of dog renin on homologus substrate. The Ki value was 7.7 X 10(-7) M and the mode of the inhibition was non-competitive. Pestatin A suppressed angiotensin I generation in dog plasma. Dose-dependent hypotensive effect of pepstatin A was observed in rats with sustained increase in blood pressure during continuous infusion of dog renin. It is concluded that pepstatin A inhibits the dog renin activity in vitro and in vivo.