Lack of evidence for linkage of the endothelial cell nitric oxide synthase gene to essential hypertension.

Background: The basal release of nitric oxide by the endothelium plays an important role in regulating blood flow and pressure and mediates most of the endothelium-dependent vasodilation. Impairment of nitric oxide production by specific inhibitors increases blood pressure in humans, and several reports suggest that hypertensive subjects have a blunted endothelium-dependent vasodilatation that might be secondary to decreased nitric oxide production from the vessel wall.

Methods And Results: To determine whether the endothelial nitric oxide synthase gene is involved in human essential hypertension, we identified informative biallelic and multiallelic markers of this locus and performed case-control and linkage studies in hypertensive subjects and normotensive control subjects.

A mutant renin gene in familial elevation of prorenin.

A case of familial elevation of plasma prorenin levels was discovered during an epidemiological survey of a Dutch population. Trypsin-activated prorenin was elevated in the 58-year-old father, his son, and one of his sisters. All family members were normotensive and had normal plasma renin activities.

Ontogeny of the two angiotensin II type 1 receptor subtypes in rats.

The two subtypes (AT1A and AT1B) of the type 1 (AT1) angiotensin II receptor mRNA were localized by in situ hybridization in rat fetal tissues from day 11 to 19 of gestation and in the young rat from day 0 to 10 postpartum, by use of 35S-labeled cRNA probes. Both subtype mRNAs were present in the kidney and in the adrenal gland. Organs such as liver, lung, heart, and undifferentiated mesenchymes expressed only AT1A mRNA.

Identification of two active site residues in human angiotensin I-converting enzyme.

Angiotensin I-converting enzyme (ACE) contains two zinc-dependent catalytic domains (N and C domains) each bearing the motif HEXXH where the two histidines form two of the three amino acid zinc ligands. Sequence alignment of each ACE domain with other zinc metalloproteases, indicates a glutamate residues which putatively constitutes the third zinc ligand and an aspartate residue which may form an indirect zinc interaction. We investigated the functional roles of the glutamate and aspartate residues in the ACE C domain (Glu987 and Asp991) using a cDNA encoding an inactive N domain.

Tissue-specific expression of type 1 angiotensin II receptor subtypes. An in situ hybridization study.

The angiotensin II type 1 (AT1) receptor in murine species exists as two isoforms (AT1A and AT1B) encoded by two different genes. Both subtypes have a 9/10 homology in the coding sequence of their mRNA. We examined organs of adult rats (liver, pituitary gland, adrenal gland, kidney, heart, and lung) to study the differential expression of these two genes in target tissues for angiotensin II.

Tissular expression and regulation of type 1 angiotensin II receptor subtypes by quantitative reverse transcriptase-polymerase chain reaction analysis.

Recent studies have revealed that angiotensin II (Ang II) interacts with two pharmacologically different types of seven-transmembrane domain receptors, hence named Ang II type 1 and type 2 (AT1 and AT2) receptors. cDNAs for the AT1 receptor have been cloned, and the existence of two receptor subtypes, AT1A and AT1B, has been revealed in rat and mouse. This study presents a new approach for the specific quantification of AT1A and AT1B receptor mRNAs by reverse transcription and polymerase chain reaction amplification in the presence of an AT1 receptor mutant cRNA as internal standard.

Discrepancy between plasma and lung angiotensin-converting enzyme activity in experimental congestive heart failure. A novel aspect of endothelium dysfunction.

The renin-angiotensin and cardiac natriuretic systems play an important role in the pathophysiology of congestive heart failure (CHF). The status of the membrane-bound pulmonary and renal activities of three ectoenzymes involved in the regulation of these systems-angiotensin-converting enzyme (ACE), neutral endopeptidase (NEP), and aminopeptidase A (APA)-was investigated in Wistar rats 3 months after induction of myocardial infarction (MI) and in sham-operated (control) rats. Plasma renin activity and ACE activity, plasma angiotensin II (Ang II) levels, and atrial natriuretic factor levels were simultaneously determined.

Internalization of the rat AT1a and AT1b receptors: pharmacological and functional requirements.

The capacity of the angiotensin II (AngII) agonist [Sar1]AngII, the antagonist [Sar1-Ile8]AngII and the non-peptidic antagonist DuP753 to undergo receptor internalization were studied in Chinese hamster ovary cells expressing rat AngII type 1a or 1b receptors (AT1a or AT1b) or a mutant of AT1a (Asn74) unable to couple G-protein. In this expression system, the ligand-induced internalization of rat AT1a and AT1b are similar. Moreover, peptidic ligands, either the agonist or antagonist, induce a significant internalization of AT1 receptors, but the non-peptidic antagonist DuP753 is far less potent.

Short report: HYPERGENE: a clinical and genetic database for genetic analysis of human hypertension.

Objective: Genetic studies of essential human hypertension require the recording and management of numerous data concerning multiple hypertensive families. The present report describes a new family database, HYPERGENE, and demonstrates its potential usefulness in such a complex disease.

Methods: The database was implemented on an Apple Macintosh computer using the 4TH DIMENSION software program.

Angiotensin II type 1 receptor gene polymorphisms in human essential hypertension.

We conducted the present study to determine whether the angiotensin II type I receptor (AT1) gene might be implicated in human essential hypertension by using case-control and linkage studies. The entire coding and 3' untranslated regions of the AT1 receptor gene (2.2 kb) were amplified by polymerase chain reaction and submitted to single-strand conformation polymorphism in 60 hypertensive subjects with a familial susceptibility.

Renin-secreting tumors.

An analysis of the renin-secreting tumors published in the literature suggests the diagnosis of JGC tumor should be evoked systematically in a young patient with severe hypertension and hypokalemia in whom a renovascular lesion has been eliminated by arteriography. A very high PRA usually is observed and blood pressure drops during converting enzyme treatment. Under acute administration of captopril, plasma renin may or may not increase, showing the inconsistency of the secretory autonomy of the tumor.

cis-regulatory elements and trans-acting factors directing basal and cAMP-stimulated human renin gene expression in chorionic cells.

Much knowledge was accumulated in the regulation of plasma renin activity and renin secretion during recent years. However, the mechanisms of renin gene transcription, especially for the human gene, have been poorly studied because of the lack of cell lines expressing renin. Cells derived from chorion tissue were used to study renin gene transcription because these cells express renin and regulate renin secretion in a similar way to JG cells.

[Cell receptors: major concepts].

There are two large categories of cell receptors, nuclear receptors and membrane receptors. Nuclear receptors are activated by steroid hormones and vitamin A. They lead to profound and lasting modifications in gene expression.

[Cellular information and communication: receptors coupled to g-proteins].

A general model for membrane receptor action mechanisms indicates that information detected by receptors in the cell plasma membrane is transmitted to biological effectors, normally mediated by coupling elements. Seven-site transmembrane receptors coupled to G-proteins likely represent the most conserved and diversified category of membrane receptors. Information transfer from the extracellular medium to the cell involves three membrane proteins: a receptor, a G-protein (which binds and hydrolyzes GTP during its cycle), and an effector that regulates intracellular ion levels or second messengers.

Synthetic cDNA encoding the rat AT1a receptor: a useful tool for structure-function relationship analysis.

To carry out systematic structure-function studies of the rat angiotensin II receptors by site directed mutagenesis, or production of chimeric receptors, we have produced a synthetic cDNA coding for the AT1a receptor. The synthetic cDNA is 1101 base pairs long, and contains 49 unique restriction sites that are on the average 23 base pairs apart, allowing replacement of specific restriction fragments by synthetic counterparts containing the desired modified sequence. The total cDNA was assembled in the expression vector pECE.

Expression of PC2 and PC1/PC3 in human pheochromocytomas.

Expressions of two Kex2-related proteases, Pc2 and PC1/PC3, and of one of their possible substrates, proenkephalin, were examined in normal (n = 7) and various pathological (n = 48) human adrenal tissues. Northern blot analysis detected the expression of these genes in pheochromocytomas only. In the 20 pheochromocytomas studied with this technique, PC2, PC1/PC3 and proenkephalin were expressed in 85%, 50% and 90%, respectively.

The enigma of pseudohypoaldosteronism.

The syndrome of primary pseudohypoaldosteronism (PHA) is a hereditary disease characterized by increased aldosterone secretion associated with clinical signs of hypoaldosteronism. These include salt wasting and failure to thrive in the newborn, high urinary sodium, hyponatremia, hyperkalemia, and metabolic acidosis. Plasma renin activity is usually elevated in association with aldosterone.

Distribution of type 1 angiotensin II receptor subtype messenger RNAs in the rat fetus.

The localization of the two type 1 angiotensin II receptor subtype (AT1A and AT1B) messenger RNAs in the 19-day-old rat fetus was studied by in situ hybridization. AT1 receptor mRNAs were detected in target organs of the renin-angiotensin system such as the kidney, adrenal gland, liver, heart, large arteries, and pituitary gland. In addition, angiotensin II receptors were present in specialized mesenchymal cells surrounding the cartilage, in the pericardium, in the lung, and in the undifferentiated mesenchymal tissue.

A recombinant form of angiotensin converting enzyme expressed from baculovirus-infected insect cells.

A secreted form of the C-domain of angiotensin converting enzyme has been expressed from the baculovirus-infected insect cell system. This soluble enzyme was purified by affinity chromatography and characterised in terms of its carbohydrate side chains and binding of substrates and inhibitors.

Co-expression of PC2 and proenkephalin in human tumoral adrenal medullary tissues.

Expression of PC2, a Kex2-related protease, and of one of its possible substrates, proenkephalin, was examined in normal adrenal glands (n = 7) and pheochromocytomas (n = 20). PC2 could only be detected in normal adrenal glands using the sensitive RT/PCR technique. By Northern blot, PC2 and proenkephalin were expressed in 85% and 90% of the 20 pheochromocytomas studied, respectively.

HYPERGENE: a clinical and genetic database for genetic analysis of human hypertension.

Objective: Genetic studies of essential human hypertension require the recording and management of numerous data concerning multiple hypertensive families. The present paper describes a new family database, HYPERGENE, and demonstrates its potential usefulness in such a complex disease.

Methods: The database was implemented on an Apple Macintosh computer using the 4TH DIMENSION software program.

Compared properties of trandolapril, enalapril, and their diacid metabolites.

The effects of 14-day trandolapril or enalapril treatment of spontaneously hypertensive rats (SHRs) were studied on blood pressure and angiotensin-converting enzyme (ACE) activity measured ex vivo in various organs. Both ACE inhibitors caused dose-dependent decreases in blood pressure and ACE activity, trandolapril being 30- and 400- to 1,000-fold more active than enalapril on blood pressure and ACE activity, respectively. However, comparison of ACE inhibitory activities of the diacid forms of trandolapril and enalapril, i.

Proteolytic release of human angiotensin-converting enzyme. Localization of the cleavage site.

Angiotensin-converting enzyme (EC 3.4.15.