kri-1314 and Hypertension

The effect of highly purified recombinant human renin (rh-renin), expressed in Chinese hamster ovary cells, on mean blood pressure (MBP) was evaluated in pithed spontaneously hypertensive rats (SHR) and Wistar-Kyoto rats (WKY). Intravenous bolus injection of rh-renin produced dose-dependent increases in MBP in pithed SHR and WKY. The pressor response to rh-renin in pithed SHR was about 3 times as potent as that in pithed WKY. Intravenous infusion of rh-renin produced dose-dependent progressive increases in MBP during the first 40 min, reaching plateaus and thereafter MBP was maintained up to 120 min. This hypertensive response to rh-renin was antagonized by renin inhibitors, YM-21095 and KRI-1314, which inhibited the reaction between rh-renin and tetradecapeptide competitively, with Ki values of 5.1 x 10(-10) and 4.3 x 10(-9) M, respectively. In rh-renin-infused pithed SHR, the hypotensive effect of YM-21095 was 37 times as potent as that of KRI-1314. These results suggest that rh-renin can stimulate the rat renin-angiotensin system, thereby producing hypertension. Moreover, the rh-renin-infused rat model could be useful to evaluate the effect of renin inhibitor.

Topics: Animals; Blood Pressure; CHO Cells; Cricetinae; Decerebrate State; Dipeptides; Hypertension; Infusions, Intravenous; Injections, Intravenous; Male; Morpholines; Naphthalenes; Rats; Rats, Inbred SHR; Rats, Inbred WKY; Recombinant Proteins; Renin

In our continuing search for low molecular weight, human renin inhibitors, a dipeptide derivative, morpholino-naphthyl-acyl-histidyl-cyclohexyl-norstatine (KRI-1314), was newly synthesized and estimated for oral effectiveness. This compound inhibited plasma renin from humans and from Japanese monkeys in vitro, with 50% inhibitory concentrations (IC50) of 4.7 x 10(-9) and 2.4 x 10(-8) mol/l, respectively. The mean blood pressure of sodium-depleted Japanese monkeys was lowered significantly after intravenous injection or oral administration of KRI-1314. The maximum reduction was attained 3 h after oral administration at a dose of 10 mg/kg. Plasma renin activity (PRA) was halved 1 h after oral administration of KRI-1314, and this inhibition persisted for more than 5 h. results suggest that KRI-1314, a potent, orally effective and long-lasting renin inhibitor, may become one of a new class of antihypertensive agent.

Topics: Administration, Oral; Animals; Antihypertensive Agents; Blood Pressure; Dipeptides; Female; Humans; Hypertension; Macaca; Male; Morpholines; Naphthalenes; Renin; Sodium