[Is the renin-angiotensin system implicated in the hypertensive effect of a water-soluble tissue extract?]

A deproteinized hydrosoluble splenic extract, which produces a hypertensive effect, injected in rats intravenously is described. The pressure action is very similar to the synthetic angiotensin II, and the (Sarcosine1-Isoleucine8)--angiotensin II, a competitive antagonist, produced partial inhibition of both responses. There were no significant differences between control and experimental rats in the plasmatic levels of angiotensin II, aldosterone and ADH. Therefore, the splenic extract does not seem to release these hormones included in the renin-angiotensin pathway. Significant Angiotensin II levels were detected in the splenic material. These results support the view that forty per cent of the pressure action is due to Angiotensin II present in the extract.