Retinal angiotensin II and angiotensin-(1-7) response to hyperglycemia and an intervention with captopril.

Hypothesis: Hyperglycemia decreases angiotensin-(1-7), the endogenous counter-regulator of angiotensin II in the retina.

Materials And Methods: The distribution and levels of retinal angiotensin II (Ang II) and angiotensin-(1-7) (Ang-(1-7)) were evaluated by confocal imaging and quantitative immunohistochemistry during the development of streptozotocin-induced diabetes in rats.

Results: In the nondiabetic eye, Ang II was localized to the endfeet of Müller cells, extending into the cellular processes of the inner plexiform layer and inner nuclear layer; Ang-(1-7) showed a wider distribution, extending from the foot plates of the Müller cells to the photoreceptor layer.

Tissue-specific expression of transgenic secreted ACE in vasculature can restore normal kidney functions, but not blood pressure, of Ace-/- mice.

Angiotensin-converting enzyme (ACE) regulates normal blood pressure and fluid homeostasis through its action in the renin-angiotensin-system (RAS). Ace-/- mice are smaller in size, have low blood pressure and defective kidney structure and functions. All of these defects are cured by transgenic expression of somatic ACE (sACE) in vascular endothelial cells of Ace-/- mice.

Angiotensin II and its receptor subtypes in the human retina.

Purpose: To quantify and evaluate the distribution of angiotensin II (Ang II) and its receptors in the human retina.

Methods: Donor eyes were obtained within 12 hours postmortem and classified as hypertensive or normotensive and diabetic or nondiabetic, based on the donors' medical histories. Ang II in retina and vitreous was quantified by RIA.

Vascular expression of germinal ACE fails to maintain normal blood pressure in ACE-/- mice.

Maintenance of normal blood pressure is critical for preserving the integrity of the cardiovascular system. Angiotensin 1-converting enzyme (ACE) regulates normal blood pressure and fluid homeostasis through its action in the renin-angiotensin-aldosterone system (RAAS) and the renal tubuloglomerular feedback response. Although the two structurally related isozymic forms of ACE both generate the vasoactive octapeptide angiotensin II (Ang II) with equal efficiency, both are expressed in a nonoverlapping tissue-restricted fashion.

Glucose utilization by the retinal pigment epithelium: evidence for rapid uptake and storage in glycogen, followed by glycogen utilization.

Glucose utilization and glycogen metabolism by human retinal pigment epithelium (RPE) cultures with high transepithelial resistance maintained on porous Millicell polycarbonate filters, were quantified by fluorophore-assisted carbohydrate electrophoresis (FACE). Glucose uptake was more efficient at the apical surface of the RPE. The utilization of glucose when restricted to either the apical or basal medium was also evaluated.

Maintenance of normal blood pressure and renal functions are independent effects of angiotensin-converting enzyme.

Angiotensin-converting enzyme (ACE) is expressed in many tissues, including vasculature and renal proximal tubules, and its genetic ablation in mice causes abnormal renal structure and functions, hypotension, and male sterility. To test the hypothesis that specific physiological functions of ACE are mediated by its expression in specific tissues, we generated different mouse strains, each expressing ACE in only one tissue. Here, we report the properties of two such strains of mice that express ACE either in vascular endothelial cells or in renal proximal tubules.