Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.4.23.15 (renin)
 35,795 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Seventeen hypertensive patients were treated with captopril, an orally active inhibitor of converting-enzyme. All patients showed a fall in blood pressure (BP), although in some patients only after the addition of diuretics. In 2 patients a skin rash developed. One patient developed proteinuria. A renal biopsy revealed membranous glomerulopathy. Correlations were found between pretreatment plasma renin activity (PRA) and the decrease in BP, and between pretreatment PRA and the decrease in plasma aldosterone concentration (PAC). Filtration fraction (FF) fell, indicating a decrease in renal vascular resistance. Captopril decreased the sensitivity to exogenous angiotensin I (AI), dependent on the captopril dose used. The sensitivity to exogenous bradykinin increased impressively even on the lowest dose of the drug. These observations suggest extrapulmonary conversion of AI to angiotensin II (AII).
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PMID:Treatment of moderate to severe hypertensive patients with an orally active converting-enzyme inhibitor. 23 14

A 30 year old man developed renovascular hypertension and extreme elevation of plasma renin activity. Daily proteinuria ranged from 13 to 31 g. There were no criteria for the diagnosis of malignant hypertension. A primary glomerulopathy was excluded by a basically normal renal biopsy from the unprotected kidney. On electron microscopy the epithelial cell foot processes were not fused, thus ruling out simultaneous lipoid nephrosis. The source of renin was removed by means of a left nephrectomy. Following the procedure the patient became normotensive, the renin values normalized and the proteinuria disappeared. The results suggest that renin can cause significant proteinuria in man.
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PMID:Renin-induced massive proteinuria in man. 45 23

Differential solute clearances were used to examine the effects of a 90-day course of enalapril on glomerular barrier function in 16 proteinuric patients with diabetic glomerulopathy. By day 90, plasma renin and prorenin became elevated, and arterial pressure declined. Transglomerular passage of dextrans of broad size distribution (radii 28-60 A) was lowered significantly. In a subset of 8 patients, withdrawal of enalapril was followed after an additional 30 days by a return of renin levels and arterial pressure to pretreatment levels. The dextran-sieving profile also returned to baseline, becoming uniformly elevated above treated day-90 levels. A theoretical analysis of the serial dextran-sieving profiles indicated that enalapril shifted glomerular pore size distribution to smaller size. These changes in barrier size selectivity were associated with a reduction in fractional albumin and IgG clearances during enalapril therapy and a subsequent rise in these quantities after its withdrawal; urinary protein excretion rate tended to vary in parallel. We conclude that inhibition of converting enzyme in humans with established diabetic glomerulopathy diminishes glomerular permeability to proteins by enhancing barrier size selectivity. Because neither enalapril therapy nor its withdrawal influenced the glomerular filtration or renal plasma flow rates significantly, we propose that the primary action of enalapril may be to modulate the intrinsic membrane properties of the glomerular barrier.
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PMID:Effects of converting-enzyme inhibition on barrier function in diabetic glomerulopathy. 169 74

One-kidney, one-clip hypertension (1-K, 1-C HT) is initiated by increased preglomerular resistance which decreases nephron perfusion and causes several intrarenal changes that lead to increased mean arterial pressure (MAP). Elevated MAP serves to return nephron perfusion and sodium excretion to normal, so that fluid intake and output are balanced. Increased MAP usually occurs through volume homeostasis mechanisms that initially raise cardiac output and later elevate total peripheral vascular resistance via autoregulatory adjustments. However, if adequate volume is unavailable because of sodium restriction, sustained activation of the renin-angiotensin system increases blood pressure sufficiently to restore nephron perfusion. Thus, depending upon the availability of volume, renal perfusion and sodium balance can be restored either by volume retention or by increased angiotensin II (ANGII) formation and peripheral vasoconstriction. Similarities exist between 1-K, 1-C HT and low-renin essential hypertension (LRHT). In both cases, renal-pressure natriuresis is shifted to higher levels and there are marked increases in preglomerular resistance that necessitate increased MAP to maintain sodium balance. However, in 1-K, 1-C HT, there is a parallel shift of pressure natriuresis with little or no change in the slope of this curve, similar to that found in the normal-renin essential hypertension. In LRHT the slope of pressure natriuresis is decreased, indicating that blood pressure is much more salt sensitive than normal. Another difference is that PRA is low compared to normal PRA in 1-K, 1-C HT after compensatory increases in MAP. There is also no indication of glomerular membrane damage in 1-K, 1-C HT, whereas LRHT may have significant glomerulopathy, especially as hypertension progresses. These differences suggest that there may be additional factors besides preglomerular vasoconstriction involved in the etiology of LRHT. One possible factor is a reduction in nephron number in LRHT. Decreased functional nephrons would lead to glomerular hyperfiltration and increased distal tubular flow rate in the remaining nephrons, causing decreased PRA and eventually glomerular damage. Increased fractional sodium reabsorption, particularly in distal tubular segments, could also contribute to decreased PRA and cause blood pressure to be salt sensitive. These abnormalities, along with preglomerular vasoconstriction, may explain many of the characteristics of LRHT.
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PMID:Renal function in one-kidney, one-clip hypertension and low renin essential hypertension. 174 89

We have investigated 975 different grazing sections of vessels in kidney preparations of 20 rats of the Wistar strain. Half of these genetically identical animals had an insulin-deficiency diabetes induced by injection of streptozocin. The kidneys were removed for investigation after 2 and 12 weeks duration of diabetes. The vessel cross-section, wall, lumen and endothelial surface area were determined in renal arteries, arterioles and preglomerular afferent arterioles in a blind experiment. Statistically detecteable changes were found in the diabetic vessels in the early stage of the diabetes. Preglomerular afferent arterioles showed a highly significant and increasing lumen dilatation commencing after 2 weeks. Diabetic arteries and arterioles developed narrower lumina. A significant thickening of the endothelium took place at the same time in both vessel types. All three vessel regions became smaller and had thinner walls than healthy vessels as the diabetes progressed. The findings on the afferent vessels indicate that haemodynamic effects on the glomerulus are to be expected. Familial diabetic gloermulopathy begins with a reversible hyperfiltration. However, the mechanism has not been clarified in the context of the diabetic metabolic disorder, and this change is probably the haemodynamic consequence of the substantial dilatation of the preglomerular afferent arterioles. With their renin-positive segment, these arterioles are the centre of intrarenal regulation. The increase of the capillary glomerular pressure associated with the dilatation of the preglomerular afferent arterioles is a crucial factor in the development of diabetic glomerulopathy.
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PMID:Morphometric investigations on intrarenal vessels of streptozotocin-diabetic rats. 192 64

Angiotensin II is the main regulator of both glomerular haemodynamics and glomerular capillary permeability. An alteration in the function of intrarenal angiotensin II seems to be the cause of diabetic glomerulopathy in animals and humans. In order to investigate the renal effects of the angiotensin converting enzyme (ACE) inhibitor enalapril (5 mg once a day), 24 normotensive diabetic patients with persistent proteinuria, after a 3-month run-in period, were randomly allocated to receive the active drug (12 patients) or the corresponding placebo, for the 6 months. Effective renal plasma flow, glomerular filtration rate, renal vascular resistance and filtration fraction were measured at the end of the run-in and the treatment periods. Blood pressure, heart rate, urinary albumin excretion, plasma renin activity and aldosterone, blood glucose, serum fructosamine and body weight were checked monthly during the run-in and every 2 months during the treatment period. Enalapril decreased urinary albumin excretion in the normotensive diabetic patients without any changes in systemic blood pressure or glomerular haemodynamics. These results indicate that ACE inhibition interferes with the glomerular capillary permeability induced by angiotensin II.
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PMID:Angiotensin converting enzyme inhibition with a low dose of enalapril in normotensive diabetics with persistent proteinuria. 285 53

Altered glomerular metabolism of arachidonic acid (AA) has already been demonstrated in experimental nephrotoxic nephritis. The enhanced synthesis of thromboxane A2 (TxA2) in isolated glomeruli that has been found may mediate changes in renal hemodynamics. The objectives of this investigation were: to check whether glomerular AA metabolism is also altered in a model of glomerulopathy in which no leukocyte infiltration or platelet deposition could be demonstrated; to establish a correlation between the altered AA metabolism and proteinuria; and to explore whether the alteration of the prostaglandin (PG) pathway found in isolated glomeruli is an in vitro artifact or reflects a modification in vivo. We used a model of glomerular damage characterized by heavy and persistent proteinuria, which was induced in the rat by a single intravenous injection of adriamycin. At light microscopy, minimal glomerular abnormalities were found in this model. Electron microscopy showed profound alterations of glomerular epithelial cells with extensive fusion of foot processes and signs of epithelial cell activation. Electron microscopy of numerous glomeruli showed no platelet deposition or macrophage and leukocyte infiltration in this model. Isolated glomeruli from nephrotic rats studied 14 or 30 d after a single intravenous injection of adriamycin (7.5 mg/kg) when animals were heavily proteinuric generated significantly more TxB2, the stable breakdown product of TxA2, than normal glomeruli. No significant changes were found in the other major AA metabolites formed through cyclooxygenase. Urinary excretion of immunoreactive TxB2 was also significantly higher in nephrotic than in normal animals. Administration of a selective Tx synthetase inhibitor, UK-38,485, from day 14 to day 18 after adriamycin resulted in a significant reduction of proteinuria compared with pretreatment values. Glomerular synthesis and urinary excretion of TxB2 were normal during the UK-38,485 treatment. Additional experiments showed that elevated glomerular synthesis and urinary excretion of TxB2 were not a consequence of increased substrate availability. Maximal stimulation of the renin-angiotensin axis with furosemide increased glomerular TxB2 synthesis in normal rats, which was significantly lower than in nephrotic animals. Finally, experiments using a unilateral model of adriamycin nephrosis indicated that the enhancement of glomerular TxB2 synthesis is not simply a consequence of the nephrotic syndrome. We conclude that: there is an abnormality of glomerular AA metabolism in nephritic syndrome, which leads to increased TxA2 production; the increased Tx generation correlates with protein excretion and might be responsible for altering the glomerular basement membrane permeability to protein; and the alteration found in isolated glomeruli probably reflects a modification in vivo, in that urinary excretion of immunoreactive TxB2 is also consistently increased in adriamycin nephrosis.
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PMID:Increased glomerular thromboxane synthesis as a possible cause of proteinuria in experimental nephrosis. 403 7

Angiotensin II (Ang II) is the primary mediator of the renin-angiotensin system (RAS). Inappropriate control of the RAS is critically involved in the development and maintenance of hypertension and congestive heart failure. The actions of Ang II are thought to be mediated by specific surface receptors on the various target organs. At present, two receptors for Ang II have been firmly established in mammals, including man. According to current nomenclature, losartan represents the prototype antagonist of the Ang II type 1 (AT1) receptor and does not possess significant affinity for the so-called AT2 receptor. Losartan is the first of a new class of orally active, nonpeptide Ang II receptor antagonists able to very specifically and selectively inhibit the RAS while lacking the agonistic effects of the peptide receptor antagonists, e.g. sarlasin, or the bradykinin potentiating effects of the angiotensin converting enzyme (ACE) inhibitors. Virtually all of the known actions of Ang II, e.g. those defined by Ang II itself, saralasin, ACE or renin-inhibitors are blocked by losartan, emphasizing the major role of this distinct Ang II receptor subtype in mediating the responses of Ang II. The functional correlate of the AT2 receptor remains poorly understood. In several models of experimental and genetic hypertension, AT1 receptor antagonists are effective antihypertensive agents with similar efficacy to that of ACE and renin-inhibitors. In animal models of renal disease, AT1 receptor antagonists significantly decrease proteinuria, protect against diabetic glomerulopathy and increase survival in stroke-prone spontaneously hypertensive rats.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:A new class of therapeutic agents: the angiotensin II receptor antagonists. 763 3

Renal haemodynamic changes are suggested to be an early sign of diabetic glomerulopathy. The juxtaglomerular apparatus relevant to the renin angiotensin system, known to be the site of nitric oxide (NO) production, is considered to play a role in the regulation of glomerular blood flow. This study was therefore designed to clarify whether in situ expression of nitric oxide synthase (NOS) is altered in the kidney of diabetic rats. Streptozotocin-induced diabetic rats with 6, 8, 12 and 32 weeks diabetes duration and age-matched normal control rats were used. The expression of a constitutive form of NOS (cNOS, neural type) and NADPH diaphorase activity in the renal cortex were studied immunohistochemically and histochemically. Diabetic rats had lower body weight and heavier kidney mass compared to control rats at each time point examined. Mean glomerular surface area was greater in 6, 8 and 12-week diabetic rats compared to age-matched control rats. cNOS reaction was localized in the macula densa and appeared less intense in diabetic rats compared to age-matched control rats. The mean number of macula densa cells positive for cNOS in each glomerulus and in each glomerular area was significantly lower in diabetic rats compared to control rats at any time examined. In contrast, NADPH diaphorase activity was detected in both juxtaglomerular arterioles and macula densa cells. The staining reaction of NADPH diaphorase in the arterioles remained positive but appeared less intense in macula densa cells in diabetic rats. These results suggest that NO production in macula densa cells may be reduced in diabetic rats, modulating the vasodilatory function of afferent arterioles. Further investigation on the changes in inducible NOS as well as endothelial cNOS are necessary to clarify mechanisms of haemodynamic changes in the diabetic kidney.
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PMID:Expression of nitric oxide synthase in macula densa in streptozotocin diabetic rats. 881 3

Overweight/obesity represent an underestimated risk factor of renal disease. The incidence of obesity-related glomerulopathy (ORG) tremendously increased within the last decade. The first sign of renal damage in overweight conditions is microalbuminuria or proteinuria, indicating the potential risk of its progression to renal insufficiency and the development of premature cardiovascular events. In the early stage of obesity renal hemodynamics are characterized by a renal hypercirculation and glomerular hyperfiltration, particularly in the presence of hypertension. The hyperfiltration is especially harmful in patients with pre-existing inflammatory and metabolic renal disease, or under the conditions of reduced renal mass. Histopathologically, ORG is characterized by glomerulomegaly with/without signs of focal segmental glomerulosclerosis. Pathogenetically, numerous factors are involved, e.g. enhanced glomerular capillary pressure, adrenergic nerve overactivity, inappropriate activation of the renin-angiotensin-aldosterone system, insulin resistance, hyperinsulinemia and hyperleptinemia, dyslipidemia, enhanced clotting tendency and sodium retention. Diabetic nephropathy is one of the most serious complications of obesity-induced diabetes. In the industrial nations type 2 diabetes is the single most frequent cause of end-stage renal disease. After kidney transplantation, overweight/obesity is associated with a less favourable prognosis for the survival of the graft and the patient. Incidence of renal cell carcinomas is enhanced in overweight/obesity. Obesity-related renal disease may be prevented/postponed by an early weight reduction, by dietary intervention combined with physical exercise. In the advanced stages of renal disease benefits of weight reduction are minimal. Concomitant administration of angiotensin-converting-enzyme inhibitors or angiotensin II receptor 1 blockers exerts antiproteinuric effects and thereby aid in retarding the disease progression. Aimed prevention and treatment of obesity represent a challenge for the healthcare system. The concerted action of physicians, patients and the public health authorities is needed.
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PMID:[Overweight and obesity--risk factors in the development and progression of renal disease]. 1532 63


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