Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.4.15.1 (ACE)
18,300 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Cortex of rat kidney was homogenized and fractions enriched in plasma membrane, endoplasmic reticulum or brush border were prepared by several techniques of differential centrifugation. The identity and homogeneity of the membrane fragments were investigated by assaying marker enzymes and by transmission and scanning electron microscopy. Kallikrein was present in both plasma-membrane- and endoplasmic-reticulum-enriched fractions isolated by two fractionation procedures. Kallikrein was highly concentrated in a plasma-membrane fraction but was absent from the brush-border membrane of proximal tubular cells. Cells of transplanted renal tumours of the rat, originating from the proximal tubule, had no kallikrein activity. Kininase activity, angiotensin I-converting enzyme (kininase II) and angiotensinase were found in a plasma-membrane-enriched fraction and especially in the fraction containing isolated brush border. It is suggested that after renal kallikrein is synthesized on endoplasmic reticulum, it is subsequently reoriented to a surface membrane for activation and release. Renal kallikrein may enter the tubular filtrate distal to the proximal tubules. The brush-border membrane of proximal tubule is the major site of inactivation of kinins and angiotensin II..
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PMID:Isolation of membrane-bound renal enzymes that metabolize kinins and angiotensins. 18 28

Kinins and prostaglandins of the E series (PGE) have the capacity to influence renal hemodynamic and excretory events and may interact intrarenally so as to reinforce one another. Thus, in the isolated Krebs-perfused rabbit kidney we showed that addition of either bradykinin or kininogen to the perfusing fluid augments the release of a PGE-like substance and that aprotinin, a kallikrein inhibitor, reduces the release of prostaglandins evoked by kininogen but not by bradykinin. Moreover, we have observed that deoxycorticosterone, an agent which increases urinary kallikrein, enhances the urinary excretion of PGE-like substance, and that this effect is prevented by simultaneous treatment with aprotinin. These observations and our demonstration that enhanced intrarenal activity of the kallikrein-kinin system, consequent to kininase II inhibition, is associated with renal vasodilation, diuresis, and natriuresis, suggest that a coupling of kinins and prostaglandins intrarenally may be directed towards the facilitation of salt-water excretion. The interdigitation of prostaglandins and the kallikrein-kinin system may thereby constitute the essential operation of a regulatory system in which the complementary actions of these hormones antagonize the sodium retaining effect of mineralocorticoids in those states in which salt-water balance is positive.
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PMID:Interaction of mineralocorticoids, renal prostaglandins and the renal kallikrein-kinin system. 76 63

Primary hypertension is associated with a lack in renal kallikrein activity which might be one of the reasons for the blood pressure elevation. Some smaller and partially uncontrolled studies suggested that an oral substitution of glandular kallikrein lowers blood pressure by a kinin-mediated vasodilation and increased natriuresis. To test this hypothesis we treated in two studies over 100 patients with untreated mild to moderate primary hypertension (WHO I-II) for 5 resp. 12 weeks in a double blind randomized and placebo controlled manner with 1800 U glandular kallikrein orally. Blood pressure measurements were performed according to the two study designs after 3 and 5 resp. 8 and 12 weeks of treatment sphymomanometrically in the day time course. No significant changes in blood pressure by kallikrein treatment could be observed at any time. Neither renal kallikrein excretion, renin and ACE-activity nor blood glucose concentration in diabetics or non-diabetics was changed. Thus, we could undoubtedly demonstrate that oral applied glandular kallikrein has no effect on primary hypertension.
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PMID:Lack of oral kallikrein in lowering systemic blood pressure in primary hypertension. 146 64

Vasoactive hormones acting as endocrine, neuroendocrine, or local hormonal systems (intracrine, autocrine, and paracrine) are an important component of the many factors that regulate blood pressure. Hypertension may be the result of an alteration in the balance between vasodepressor and vasopressor hormonal systems. Changes in this balance could be due to genetic factors such as mutations in one of the genes of the vasoactive system or environmental factors that alter the synthesis and release of one or more vasoactive hormones. Endocrine and neuroendocrine vasopressor hormonal systems, such as the renin-angiotensin system and catecholamines, play a well-established and important role in the regulation of blood pressure and the pathogenesis of some secondary forms of hypertension. The blockade of such systems has already resulted in effective antihypertensive treatment. The role of local hormonal systems is less well established; however, recent evidence suggests they also play an important role in the regulation of blood pressure and the pathogenesis of hypertension. Some vasopressor hormonal systems, such as the renin-angiotensin system, can act as both endocrine or local hormonal systems. Work using transgenic rats harboring the mouse Ren-2 gene has conclusively demonstrated that the renin-angiotensin system, acting as a local hormonal system, has the capability to cause severe hypertension. Whether this model of experimental hypertension mimics any type of human hypertension is not known. Vasodepressor hormones such as kinins, prostaglandins, and endothelium-derived relaxing factor (EDRF) act mainly as local hormonal systems, with the notable exception of atrial natriuretic factor, which may act as both an endocrine and a local hormone. The tissue kallikrein-kinin system, acting either directly or via paracrine eicosanoids or EDRF, participates in local regulation of the circulation, renal function, and the acute antihypertensive effect of angiotensin converting enzyme inhibitors. A restriction fragment length polymorphism (RFLP) that distinguishes the kallikrein gene family of a strain of spontaneously hypertensive rats (SHR) from normotensive Brown Norway rats has been identified. In a set of 32 recombinant inbred strains derived from these SHR and Brown Norway strains, the RFLP marking the kallikrein gene family of SHR cosegregated with an increase in blood pressure. Also, in a study of Utah families it was found that a dominant-allele kallikrein gene expressed as high urinary kallikrein excretion was associated with a decreased risk of essential hypertension. In conclusion, vasopressor and vasodepressor hormones, acting not only as endocrine but also as local hormones, play an important role in the regulation of blood pressure and the pathogenesis of hypertension.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Local hormonal factors (intracrine, autocrine, and paracrine) in hypertension. 188 59

The effects of delapril, an angiotensin converting enzyme (ACE) inhibitor, on renal function and the renin-angiotensin and kallikrein-prostaglandin systems were investigated in 10 hypertensive patients who were treated for between 4 months and 1 year. There was a significant (P less than .05) increase in renal blood flow (RBF) without affecting glomerular filtration rate. Filtration fraction increased, while renal vascular resistance decreased. There were also significant (P less than .05) increases in urinary kallikrein and prostaglandin excretion, while thromboxane excretion decreased. There was no change in urinary aldosterone excretion. These results suggest that renal hemodynamic changes seen during long-term therapy with delapril are caused, in part, by activation of the kallikrein-prostaglandin system, as well as suppression of the renin-angiotensin system.
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PMID:Long-term effects of delapril on renal function and urinary excretion of kallikrein, prostaglandin E2, and thromboxane B2 in hypertensive patients. 200 49

The effects of inhibiting angiotensin converting enzyme with perindopril and aldosterone with spironolactone were tested in hypertensive patients over fifty. Accordingly, 75 patients with mild hypertension aged 50 to 70 were randomly divided into three groups for a double-blind 8 week comparison of the actions of placebo, 4 to 8 mg/day perindopril, and 37.5 to 75 mg/day spironolactone. Side-effects caused one patient to withdraw from placebo and one from spironolactone treatment. Mean blood pressure rose by 2.4 mm Hg after placebo but dropped by 7.4 and 8.6 after perindopril and spironolactone (P less than .01). Placebo, perindopril, and spironolactone did not alter blood glucose or plasma potassium, but induced, respectively, variations of -0.09, 0, and +0.34 mmol/L in cholesterol (P = .04), and -0.02, -0.05, and +0.27 mmol/L in triglycerides (P less than .01). After the three treatments, changes in angiotensin converting enzyme activity averaged -1, -6, and -1 mU/mL (P less than .01), in active renin -2, +18, and +28 pg/mL (P less than .01), and in aldosterone, +15, +8, and +95 pg/mL (P less than .01). Placebo, perindopril, and spironolactone did not alter microalbuminuria, but reduced urinary kallikrein activity by 0.9, 1.8, and 5.4 mU/mmol creatinine (P = .04). Although short-term administration of spironolactone raised renin and aldosterone markedly and lipids moderately (possibly because of volume contraction), the present results show that perindopril and spironolactone are both safe and effective for treating hypertension at the age of 50 or older.
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PMID:Are angiotensin converting enzyme inhibition and aldosterone antagonism equivalent in hypertensive patients over fifty? 205 95

A newly synthesized orally active renin inhibitor, N-morpholinoacetyl-(1-naphthyl)-L-alanyl-(4-thiazolyl)-L-alanyl (3S,4S)-4-amino-3-hydroxy-5-cyclohexylpentanoyl-n-hexylamide (ES-8891), was found to be a highly potent competitive inhibitor of human renin with an inhibition constant of 1.1 nM. This inhibitor was also active against monkey renin, although there was less inhibition of renin in pig, rabbit, and rat. ES-8891 did not inhibit cathepsin D, pepsin, trypsin, chymotrypsin, angiotensin converting enzyme, and urinary kallikrein at a concentration of 10(-5) M. A single oral administration of ES-8891 (10 or 30 mg/kg) to conscious, sodium-depleted marmosets caused a dose-related decrease in plasma renin activity and blood pressure. ES-8891 (30 mg/kg) produced an 80% inhibition of plasma renin activity, which lasted for more than 6 hours. Kidney renin messenger RNA was not significantly changed 6 hours after oral administration of ES-8891 (30 mg/kg). A single oral administration of 240 mg ES-8891 to healthy human volunteers (n = 6) produced a significant inhibition of plasma renin activity (75% inhibition at 0.5 and 1 hour, 50% inhibition at 2 hours) with a good correlation of plasma levels of ES-8891. There were no significant changes in blood pressure or heart rate, and no adverse effects were observed. These results suggest that ES-8891 is an orally active human renin inhibitor that may be clinically useful.
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PMID:ES-8891, an orally active inhibitor of human renin. 211 12

1. An in vitro experiment was carried out to compare the inhibitory effect of SQ29,852 on human renal angiotensin converting enzyme (ACE) with those of captopril, enalapril and enalaprilat. 2. SQ29,852 strongly inhibited human renal ACE; its IC50 value was 1.5 x 10(-8) M. In terms of the IC50, SQ29,852's efficacy was about 1/10 of that of captopril and 1/28 of that of enalaprilat, but it was about 14 times more potent than enalapril. 3. SQ29,852 showed no inhibitory effects on cathepsin D, urinary kallikrein, renal renin, pepsin, trypsin and chymotrypsin. Its ACE-specificity was higher than that of captopril. 4. ACE inhibition by SQ29,852 was shown to be competitive, as revealed by Lineweaver-Burk plots. The affinity of SQ29,852 to ACE was shown to be high by a Ki value of 1.2 x 10(-8) M.
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PMID:Effect of SQ29,852, a new angiotensin converting enzyme (ACE) inhibitor with a phosphonic acid group, on the activity of angiotensin converting enzyme from human kidney. 216 61

The effects of a new angiotensin converting enzyme inhibitor, delapril hydrochloride, (delapril) on renal function, and the renin-angiotensin-aldosterone and kallikrein-kinin prostaglandin systems were studied in 10 hypertensive patients. After 4 to 12 months (7.6 +/- 0.9 [SE]) of treatment with 15-60 mg/day (36 +/- 6.8) of delapril (b.i.d.), mean arterial pressure was decreased from 126 +/- 3.0 to 110 +/- 4.4 mmHg (p less than 0.01). Although renal blood flow (RBF), assessed by PAH clearance and hematocrit, was increased from 437 +/- 51 to 490 +/- 49 ml/min (p less than 0.05) and renal vascular resistance was decreased (p less than 0.05), glomerular filtration rate, measured by endogenous creatinine clearance, did not change significantly. Thus, filtration fraction was reduced (p less than 0.01). Plasma renin activity was increased from 1.5 +/- 0.3 to 4.4 +/- 1.1 ng/ml/hr (p less than 0.01). Plasma aldosterone concentration tended to decrease (p less than 0.1), and urinary aldosterone excretion showed on significant change. Although urinary kallikrein and prostaglandin E2 excretions were increased (p less than 0.05), urinary thromboxane B2 excretions was reduced (p less than 0.05). In addition, the changes in RBF were significantly correlated with those in urinary PGE2 excretion (r = 0.63, p less than 0.05). These results suggest that the antihypertensive effect of delapril is multifactorial and that the improvement of RBF seen during delapril administration in the present study may be partly due to the suppression of the renin-angiotensin-aldosterone system and the activation of kallikrein-kinin-prostaglandin system.
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PMID:[The long-term effects of a new converting enzyme inhibitor, delapril hydrochloride, on renal function, renin-angiotensin-aldosterone system and kallikrein-kinin prostaglandin system in hypertensive patients]. 227 96

Inhibition of the kallikrein-kinin system with aprotinin, and measurements of urinary kallikrein and kinin excretion, were used to examine a possible involvement of endogenous kinins in mediating the acute antihypertensive and renal actions of captopril in conscious, unstressed spontaneously hypertensive rats (SHR). Captopril, 30 mg/kg + 300 micrograms/kg/min, caused an acute significant decrease in mean arterial pressure. Urinary kallikrein excretion tended to decrease, while kinin excretion tended to decrease, while kinin excretion tended to increase after captopril, without reaching statistical significance. Renal water and electrolyte excretion remained practically unchanged. Aprotinin, 1,000 KIU/kg/min, had no effect on mean arterial pressure, whereas it decreased urinary kallikrein activity to undetectable levels and lowered kinin excretion by 21% (p less than 0.05). Urine flow remained unchanged, but sodium/potassium excretion ratio increased significantly during aprotinin infusion. When captopril and aprotinin were infused in combination, the decrease in mean arterial pressure was not significantly different from that seen when captopril was given alone. Although urinary kallikrein activity decreased below the detection limit of our assay, urinary kinin, as well as water and electrolyte excretion, remained relatively stable during the combined infusion. The present results provide direct evidence that the acute antihypertensive effect of captopril in conscious SHR is probably not due to an increased kinin accumulation secondary to the inhibition of kininase II. Our findings also suggest that under basal conditions intrarenal renin-angiotensin and kallikrein-kinin systems may play a minor role, if any, in the regulation of renal water and electrolyte excretion.
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PMID:Antihypertensive and renal effects of captopril in spontaneously hypertensive rats: evidence against a role of the kallikrein-kinin system. 244 Nov 74


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