ANGIOTENSIN AND RENO-PORTAL ANASTOMOSIS

Effect of converting enzyme inhibition with captopril on in vitro angiotensin production in sheep

1. The effect of captopril on in vitro production of angiotensin I (ANG I), [Val5]-angiotensin II ([Val5]-ANG II) and [Val4]-angiotensin III ([Val5]-ANG-(2-8)) in central venous blood taken from sodium-deficient sheep was studied. 2. Captopril enhances in vitro production of ANG I but blocks the in vitro production of [Val5]-ANG II and [Val5]-ANG-(2-8). 3. The production of ANG I in blood is faster than that of [Val5]-ANG II and [Val5]-ANG-(2-8). 4. The half-life of [Val5]-ANG II and [Val5]-ANG-(2-8) in vitro in blood in the presence of captopril was 10 and 14 min, respectively. 5. This in vitro study suggests that the production of [Val5]-ANG II and [Val5]-ANG-(2-8) in blood forms a small part of the total body production of each peptide.

[Metabolism of angiotensin II during angiotensin infusion and following sodium depletion]

1. Angiotensin II (A II) and angiotensin (3--8)-hexapeptide (H) were measured by radioimmunoassay in arterial and venous plasma before and during infusion of angiotensin II-amide in five normotensive subjects, both in sodium-replete and sodium-depleted states. The separation of the oligopeptides was performed by thin layer chromatography. 2. Before sodium-depletion the mean ratio of arterial to venous A II was 1.14+/-0.11:1, corresponding to an A II-extraction of approximately 12% during a single forearm passage. Infusion of A II-amide increased extraction of A II. The mean ratio of arterial to venous A II increased to 1.68+/-0.3:1, corresponding to an extraction of approximately 39% when 8 ng-min-1-kg-1 were infused. 3. Sodium depletion increased arterial and venous concentrations of A II and H. During infusion of angiotensin II-amide the arterial and venous concentrations of A II and H increased approximately parallel to the concentrations before sodium depletion. The extraction of A II did not differ significantly in both states. 4. The augmented extraction extraction of A II observed during infusion of angiotensin II-amide suggest an overproportional increase of the metabolism of A II under the latter condition. Sodium depletion, however, does not appear to cause a percent change in A II metabolism.

O comportam en to da pressão arterial na esquistossomose hepática e outras hepatopatias

O estudo de 911 pacientes hospitalizados para tratamento de variados casos de patologia interna mostrou 26,8% de hipertensos e 34,7% de doentes com alteração hepática, 17,7% dêstes apresentando hepatopatia esquistossomótica. A análise das observações resultem, na seleção de seis casos em que havia a coexistência de hipertensão e hepatopatia e que são estudados em separado. Outros seis casos foram encontrados em que a necrópsia revelou alteração hepática e o "rim da hipertensão essencial", mas em cujas observações clinioas não constava qualquer evidência de doença hipertensiva. A comparação da média das pressões arteriais mostrou diferença estatisticamente significante para as pressões sistólicas e diastólicas, sendo mais altas entre os pacientes não hepatopatas. Fêz-se, também, minuciosa revisão da literatura.