The hormonal renin-angiotensin system (RAS) has important physiological functions, which are related directly and indirectly to the regulation of blood pressure, fluid and electrolyte balance [1]. The potent vasoconstrictor action of angiotensin II (Ang II) originates from hepatic precursor angiotensinogen, where it is cleaved by the renal enzyme renin in the circulating blood. The product, Ang...

Previous studies have indicated that angiotensin II (Ang II) concentrations in renal interstitial fluid are much higher than plasma levels. In the present study, we performed experiments to explore renal interstitial fluid concentrations of Ang I and Ang II further and to determine whether these levels are altered by acute arterial infusion of an ACE inhibitor (enalaprilat) or by volume expansi...

Evidence of biological activity of fragments of ANG II is accumulating. Fragments considered being inactive degradation products might mediate actions previously attributed to ANG II. The study aimed to determine whether angiotensin fragments exert biological activity when administered in amounts equimolar to physiological doses of ANG II. Cardiovascular, endocrine, and renal effects of ANG II,...

The existence of angiotensin II (AII) immunoreactivity in juxtaglomerular (JG) cells of rat kidney, which has been demonstrated previously by immunohistochemical studies, can be explained either as the product of intracellular synthesis or by the internalization of receptor-bound AII originating in plasma. To resolve these two alternative mechanisms, attempts were made to identify AI in JG cell...

Neurons from mouse models of Huntington's disease (HD) exhibit altered electrophysiological properties, potentially contributing to neuronal dysfunction and neurodegeneration. The renin-angiotensin system (RAS) is a potential contributor to the pathophysiology of neurodegenerative diseases. However, the role of angiotensin II (Ang II) and angiotensin (1-7) has not been characterized in HD. We i...

For several years it was believed that angiotensin II (Ang II) alone mediated the effects of the renin-angiotensin system. However, it has been observed that other peptides of this system, such as angiotensin-(1-7) (Ang-(1-7)), present biological activity. The effect of Ang II and Ang-(1-7) on renal sodium excretion has been associated, at least in part, with modulation of proximal tubule sodiu...