Inhibition of renin in the primate Callithrix jacchus (common marmoset)

The effects of an antiserum against human kidney renin and of H-142, a peptide inhibitor of human renin, were studied in the primate Callithrix jacchus (common marmoset). In severely volume-depleted (low-salt diet and repetitive injections of furosemide), conscious marmosets, the antiserum reduced blood pressure to the same extent as the converting enzyme inhibitor teprotide (-31 +/- 7 SEM mmHg and -30 +/- 5 mmHg). In mildly volume-depleted (normal salt diet and single injection of furosemide), conscious marmosets, H-142 and teprotide induced a similar fall in blood pressure (-14 +/- 4 mmHg and -15 +/- 2 mmHg). When H-142 was infused after the injection of teprotide, it had no further effect on blood pressure. Conversely, teprotide was ineffective when injected during the infusion of H-142. These results show that in marmosets blood pressure can be lowered by specific inhibitors of human renin. A converting-enzyme inhibitor has similar effects. Hence the renin-angiotensin system appears to contribute significantly to the maintenance of blood pressure in conscious, volume-depleted marmosets.