RESUMO
In 55 rats, not accustomed to the process of blood pressure measurement and given daily doses from 1.25 - 10.0 mg angiotensin in depot form for up to 3 days, as much as 70% of the animals died of circulatory failure. Blood pressure increase was either absent or was very low after low doses. Histologically, the myocardium revealed focal destruction of muscle fibres with mesenchymal cell proliferation in many places; the epithelium of numerous renal tubuli was changed hydropically; the liver showed focal necroses of the parenchyma; the adrenal cortex showed stress reactions, and the arterioles of the splanchnic area -- changes of the plasmatic vasculose from the 3rd day of experiment. By contrast, in 51 rats accustomed to the measuring process prior to the experiment and given high doses of angiotensin, only moderate blood pressure rise and scattered cases of death (4%) occurred, low doses caused a strong blood pressure elevation. With otherwise equal histologic organ diagnoses, liver necroses were absent, except for two cases. This differential response of the two animal groups to varying angiotensin doses and the pathogenesis of the changes observed are discussed.
