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)

The bolus ip. administration of a SRIF antagonist (SRIF-A) (60 nM/rat) significantly increased renin activity (PRA) and plasma aldosterone concentration (PAC) in rats, without affecting natremia, kalaemia and the blood levels of ACTH or corticosterone. SRIF-A also raised PAC in rats whose renin-angiotensin system had been pharmacologically interrupted by combined captopril/angiotensin-II infusion and in which PRA was very low. The ip. injection of an equimolar dose of SRIF completely reversed these effects of SRIF-A, but the administration of SRIF alone did not affect either PRA or PAC. Taken together, these data would suggest that, in the rat, endogenous SRIF exerts, under basal conditions, a two-fold maximum tonic inhibitory effect on both renin release by kidneys and aldosterone secretion by zona glomerulosa cells.
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PMID:Evidence that endogenous somatostatin (SRIF) exerts a tonic inhibitory effect on the rat renin--angiotensin--aldosterone system. 135 7

Tissue and secreted forms of rat prosomatostatin and its cleavage products were characterized immunochemically using high performance liquid chromatography and sequence-specific radioimmunoassays directed against somatostatin-14 (S-14), S-28-(1-12), and S-28-(1-14). Acetic or hydrochloric acid extracts of hypothalamus, pancreas, stomach, and jejunum contained seven molecular forms of Mr = 10,400 (corresponding to prosomatostatin (pro-S], Mr = 6,800 (7-kDa peptide, consisting of an NH2-terminally truncated form of pro-S), Mr = 7,600 (8-kDa peptide, corresponding to pro-S-(1-76), i.e. pro-S minus the COOH-terminal -Arg-Lys-S-14), Mr = 5,600 (5-kDa peptide, corresponding to pro-S-(33-76)) and three peptides co-chromatographing with synthetic S-14, S-28, and S-28-(1-12). Acid/ethanol extracts of these tissues contained pro-S, 8-kDa peptide, S-28, S-14, and S-28-(1-12) forms, but not the 7- and 5-kDa species. Pepstatin inhibited 7- and 5-kDa peptide formation in acetic acid extracts of tissues. The secreted forms consisted of the same five forms present in acid/ethanol or acetic acid plus pepstatin tissue extracts. The 7- and 5-kDa peptides were not secreted and appeared to be derived artifactually, presumably through the action of renin- and cathepsin D-like acid proteases. Accurate quantitation of the 8-kDa peptide by acid/ethanol extraction revealed a variable tissue distribution. Since the presence of the 8-kDa form provides evidence for direct processing of pro-S----S-14 + 8-kDa peptide, the present data suggest that pro-S----S-14 conversion is important for S-14 synthesis in the hypothalamus and pancreas, tissues rich in the 8-kDa form, but not in the stomach and jejunal mucosa, which contain low concentrations of this peptide.
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PMID:Peptides derived from cleavage of prosomatostatin at carboxyl- and amino-terminal segments. Characterization of tissue and secreted forms in the rat. 289 3

IRCM-serine protease 1 (SP1), originally isolated from porcine pituitaries and exhibiting preference for cleavage at pairs of basic residues has now been isolated in sufficient quantities to be structurally characterized from both porcine and human pituitaries and plasmas. Whereas the porcine protease shows a high degree of amino acid sequence homology to human plasma pre-kallikrein, the human homologue exhibits an identity of sequence in the first 25 residues of each chain (regulatory and catalytic chains). In addition, human plasma and pituitary IRCM-SP1 and human plasma pre-kallikrein show virtually identical immunological and molecular properties. These data strongly suggest that IRCM-SP1 and plasma pre-kallikrein originate from the same gene product. Purified extracts from perfused rat pituitaries show that 32% of the IRCM-SP1 activity found in normal rat pituitaries, still remain. These data together with the demonstrated association of IRCM-SP1 with particulate fractions of the pituitary suggest that IRCM-SP1 represents a tissue form of plasma pre-kallikrein. The characterization of the digestion products obtained upon reaction of IRCM-SP1 with pro-insulin, ACTH1-39, pro-dynorphin and pro-enkephalin-derived peptides, somatostatin-28, and a pro-renin-like peptide confirmed the high degree of cleavage selectivity of this enzyme for pairs of basic residues.
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PMID:Structural and immunological homology of human and porcine pituitary and plasma IRCM-serine protease 1 to plasma kallikrein: marked selectivity for pairs of basic residues suggests a widespread role in pro-hormone and pro-enzyme processing. 296 54

It has been demonstrated that somatostatin (SRIF) can suppress hypophyseal and extrahypophyseal hormones; moreover, many studies have shown that SRIF inhibits frusemide-induced hyperreninemia in normal man, and renin and aldosterone in renovascular hypertension, possibly through a beta-adrenergic block. To further investigate the possible aldosterone-inhibiting effect of somatostatin, we have carried out in vitro studies using isolated perfused rat zona glomerulosa cells suspended in Bio-gel. Paired columns were set up and the cells stimulated using either angiotensin II, ACTH, serotonin or potassium. One column was perfused with somatostatin (3-4 ng/ml) and the other was used as a control. Aldosterone was measured by highly specific direct radioimmunoassay. Somatostatin significantly blocked the aldosterone response to angiotensin II but not to ACTH, serotonin or potassium. The inhibitory effect of somatostatin persisted as long as it was added to the medium; the aldosterone response to angiotensin II was progressively restored after discontinuation of the SRIF infusion. From these data it might be suggested that the inhibitory effect of somatostatin on aldosterone production is not cAMP-dependent, since ACTH maintains its stimulatory capacity. The recent demonstration of the presence of specific somatostatin receptors on the rat adrenal cells suggests that its inhibitory effect could be mediated by the second messenger system rather that the interaction with angiotensin II receptors.
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PMID:Inhibitory effect of somatostatin on the aldosterone response to angiotensin II: in vitro studies. 612 38

The effect of SRIF and its antagonist cyclo(7-aminoheptanonyl-Phe-D-Trp-Lys-Thr magnitude of Bzl)(SRIF-A) were studied in sham-operated and bilaterally adrenalectomized rats bearing ACTH- and angiotensin II (ANG-II)-responsive adrenocortical autotransplants. SRIF-A (10(-5) M) completely annulled SRIF (10(-6) M)-induced inhibition of ANG-II (10(-8) M)-evoked rise in aldosterone (ALDO) secretion by both dispersed zona glomerulosa (ZG) cells and autotransplant slices. A 7-day intraperitoneal infusion with SRIF (0.3 nmol.kg-1.min-1) significantly lowered plasma ALDO concentration (PAC) in both groups of animals, without affecting plasma renin activity and the plasma levels of ACTH and corticosterone. This treatment caused a marked atrophy of adrenal ZG and its parenchymal cells (without inducing any significant change in the zona fasciculata morphology), as well as of ZG-like cells of autotransplants. Isolated ZG cells and autotransplant slices from SRIF-infused rats evidenced a notable decrease in both their basal and maximally ACTH- or ANG-II-stimulated ALDO production. The simultaneous infusion of rats with SRIF-A (3 nmol.kg-1.min-1) completely reversed all these effects of SRIF. The prolonged infusion with SRIF-A alone caused, in sham-operated rats, a marked increase in PAC and a significant hypertrophy of ZG and ZG cells; basal and maximally-stimulated ALDO secretion of dispersed ZG cells was also notably raised. Conversely, SRIF-A infusion did not evoke any appreciable effect in autotransplanted rats. These findings suggest that endogenous SRIF is specifically involved in the negative control of the secretion and growth of the rat adrenal ZG. Since regenerated adrenocortical autotransplants, which are responsive to SRIF but not to SRIF-A infusion, are completely deprived of chromaffin cells, the hypothesis is advanced that adrenal zona medullaris may be the source of endogenous SRIF regulating ZG function.
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PMID:Evidence that endogenous somatostatin (SRIF) exerts an inhibitory control on the function and growth of rat adrenal zona glomerulosa. The possible involvement of zona medullaris as a source of endogenous SRIF. 790 23

A soluble angiotensin (Ang) II-generating enzyme has been purified to homogeneity from the rat mesenteric arterial bed (MAB) perfusate by a combination of gel filtration and affinity chromatographies. The enzyme is a glycoprotein of 28.5 kDa (SDS-PAGE), whose N-terminal sequence is identical with that of the rat pancreatic elastase-2; therefore the enzyme will henceforth be referred to as rat MAB elastase-2. When Ang I was used as the substrate, the enzyme specifically released Ang II and the dipeptide His-Leu (Km=36 microM; Kcat=1530 min-1). The catalytic efficiency (Kcat/Km=42.5 min-1 microM-1) of this reaction was comparable to those of other known Ang I-converting enzymes. The proteolytic specificity of the purified enzyme toward mellitin, oxidized insulin B chain, somatostatin-14 and renin substrate tetradecapeptide suggested that the enzyme-substrate interaction was defined by an extended substrate binding site, typical of elastases-2 of pancreatic origin. According to the sensitivity of the rat MAB elastase-2 to various inhibitors this enzyme could be described as a member of the chymostatin-sensitive group of Ang II-forming serine proteases. The localization and biochemical properties of this enzyme suggest that it might play a role in the regional control of vascular tonus.
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PMID:Purification and substrate specificity of an angiotensin converting elastase-2 from the rat mesenteric arterial bed perfusate. 977 38