Specific and irreversible block of the myotropic action of angiotensin II

COMPETITIVE inhibitors of the octapeptide hormone angiotensin II (AT), Asp-Arg-Val-Tyr-Val-His-Pro-Phe, have been synthesised by several groups 1 . These inhibitors, like the hormone, are quickly degraded, and no irreversible or even long-acting specific inhibitors have been available. Paiva et al. 2 have attempted to produce such inhibitors using affinity labelling analogues, but with poor results. We report here a specific and irreversible inhibition of the response of rabbit aorta strips to AT by a photolabile analogue of AT.