Renin: A highly specific (Leu-Leu) endopeptidase that generates ANGIOTENSIN I from its precursor ANGIOTENSINOGEN, leading to a cascade of reactions which elevate BLOOD PRESSURE and increase sodium retention by the kidney in the RENIN-ANGIOTENSIN SYSTEM. The enzyme was formerly listed as EC System: A BLOOD PRESSURE regulating system of interacting components that include RENIN; ANGIOTENSINOGEN; ANGIOTENSIN CONVERTING ENZYME; ANGIOTENSIN I; ANGIOTENSIN II; and angiotensinase. Renin, an enzyme produced in the kidney, acts on angiotensinogen, an alpha-2 globulin produced by the liver, forming ANGIOTENSIN I. Angiotensin-converting enzyme, contained in the lung, acts on angiotensin I in the plasma converting it to ANGIOTENSIN II, an extremely powerful vasoconstrictor. Angiotensin II causes contraction of the arteriolar and renal VASCULAR SMOOTH MUSCLE, leading to retention of salt and water in the KIDNEY and increased arterial blood pressure. In addition, angiotensin II stimulates the release of ALDOSTERONE from the ADRENAL CORTEX, which in turn also increases salt and water retention in the kidney. Angiotensin-converting enzyme also breaks down BRADYKININ, a powerful vasodilator and component of the KALLIKREIN-KININ SYSTEM.Angiotensinogen: An alpha-globulin of about 453 amino acids, depending on the species. It is produced by the liver and secreted into blood circulation. Angiotensinogen is the inactive precursor of natural angiotensins. Upon successive enzyme cleavages, angiotensinogen yields angiotensin I, II, and III with amino acids numbered at 10, 8, and 7, respectively.Aldosterone: A hormone secreted by the ADRENAL CORTEX that regulates electrolyte and water balance by increasing the renal retention of sodium and the excretion of potassium.Kidney: Body organ that filters blood for the secretion of URINE and that regulates ion concentrations.Fumarates: Compounds based on fumaric acid.Angiotensin II: An octapeptide that is a potent but labile vasoconstrictor. It is produced from angiotensin I after the removal of two amino acids at the C-terminal by ANGIOTENSIN CONVERTING ENZYME. The amino acid in position 5 varies in different species. To block VASOCONSTRICTION and HYPERTENSION effect of angiotensin II, patients are often treated with ACE INHIBITORS or with ANGIOTENSIN II TYPE 1 RECEPTOR BLOCKERS.Blood Pressure: PRESSURE of the BLOOD on the ARTERIES and other BLOOD VESSELS.Angiotensin I: A decapeptide that is cleaved from precursor angiotensinogen by RENIN. Angiotensin I has limited biological activity. It is converted to angiotensin II, a potent vasoconstrictor, after the removal of two amino acids at the C-terminal by ANGIOTENSIN CONVERTING ENZYME.Angiotensins: Oligopeptides which are important in the regulation of blood pressure (VASOCONSTRICTION) and fluid homeostasis via the RENIN-ANGIOTENSIN SYSTEM. These include angiotensins derived naturally from precursor ANGIOTENSINOGEN, and those synthesized.Furosemide: A benzoic-sulfonamide-furan. It is a diuretic with fast onset and short duration that is used for EDEMA and chronic RENAL INSUFFICIENCY.Hypertension: Persistently high systemic arterial BLOOD PRESSURE. Based on multiple readings (BLOOD PRESSURE DETERMINATION), hypertension is currently defined as when SYSTOLIC PRESSURE is consistently greater than 140 mm Hg or when DIASTOLIC PRESSURE is consistently 90 mm Hg or more.Enzyme Precursors: Physiologically inactive substances that can be converted to active enzymes.Diet, Sodium-Restricted: A diet which contains very little sodium chloride. It is prescribed by some for hypertension and for edematous states. (Dorland, 27th ed)Captopril: A potent and specific inhibitor of PEPTIDYL-DIPEPTIDASE A. It blocks the conversion of ANGIOTENSIN I to ANGIOTENSIN II, a vasoconstrictor and important regulator of arterial blood pressure. Captopril acts to suppress the RENIN-ANGIOTENSIN SYSTEM and inhibits pressure responses to exogenous angiotensin.Amides: Organic compounds containing the -CO-NH2 radical. Amides are derived from acids by replacement of -OH by -NH2 or from ammonia by the replacement of H by an acyl group. (From Grant & Hackh's Chemical Dictionary, 5th ed)Hypertension, Renal: Persistent high BLOOD PRESSURE due to KIDNEY DISEASES, such as those involving the renal parenchyma, the renal vasculature, or tumors that secrete RENIN.Hypertension, Renovascular: Hypertension due to RENAL ARTERY OBSTRUCTION or compression.Sodium: A member of the alkali group of metals. It has the atomic symbol Na, atomic number 11, and atomic weight 23.Angiotensin-Converting Enzyme Inhibitors: A class of drugs whose main indications are the treatment of hypertension and heart failure. They exert their hemodynamic effect mainly by inhibiting the renin-angiotensin system. They also modulate sympathetic nervous system activity and increase prostaglandin synthesis. They cause mainly vasodilation and mild natriuresis without affecting heart rate and contractility.Peptidyl-Dipeptidase A: A peptidyl-dipeptidase that catalyzes the release of a C-terminal dipeptide, -Xaa-*-Xbb-Xcc, when neither Xaa nor Xbb is Pro. It is a Cl(-)-dependent, zinc glycoprotein that is generally membrane-bound and active at neutral pH. It may also have endopeptidase activity on some substrates. (From Enzyme Nomenclature, 1992) EC Gland: One of two salivary glands in the neck, located in the space bound by the two bellies of the digastric muscle and the angle of the mandible. It discharges through the submandibular duct. The secretory units are predominantly serous although a few mucous alveoli, some with serous demilunes, occur. (Stedman, 25th ed)Antihypertensive Agents: Drugs used in the treatment of acute or chronic vascular HYPERTENSION regardless of pharmacological mechanism. Among the antihypertensive agents are DIURETICS; (especially DIURETICS, THIAZIDE); ADRENERGIC BETA-ANTAGONISTS; ADRENERGIC ALPHA-ANTAGONISTS; ANGIOTENSIN-CONVERTING ENZYME INHIBITORS; CALCIUM CHANNEL BLOCKERS; GANGLIONIC BLOCKERS; and VASODILATOR AGENTS.Nephrectomy: Excision of kidney.Renal Circulation: The circulation of the BLOOD through the vessels of the KIDNEY.Hypertension, Malignant: A condition of markedly elevated BLOOD PRESSURE with DIASTOLIC PRESSURE usually greater than 120 mm Hg. Malignant hypertension is characterized by widespread vascular damage, PAPILLEDEMA, retinopathy, HYPERTENSIVE ENCEPHALOPATHY, and renal dysfunction.Secretory Rate: The amount of a substance secreted by cells or by a specific organ or organism over a given period of time; usually applies to those substances which are formed by glandular tissues and are released by them into biological fluids, e.g., secretory rate of corticosteroids by the adrenal cortex, secretory rate of gastric acid by the gastric mucosa.Losartan: An antagonist of ANGIOTENSIN TYPE 1 RECEPTOR with antihypertensive activity due to the reduced pressor effect of ANGIOTENSIN II.Encyclopedias as Topic: Works containing information articles on subjects in every field of knowledge, usually arranged in alphabetical order, or a similar work limited to a special field or subject. (From The ALA Glossary of Library and Information Science, 1983)Electronic Mail: Messages between computer users via COMPUTER COMMUNICATION NETWORKS. This feature duplicates most of the features of paper mail, such as forwarding, multiple copies, and attachments of images and other file types, but with a speed advantage. The term also refers to an individual message sent in this way.Food Dispensers, Automatic: Mechanical food dispensing machines.Editorial Policies: The guidelines and policy statements set forth by the editor(s) or editorial board of a publication.Authorship: The profession of writing. Also the identity of the writer as the creator of a literary production.Periodicals as Topic: A publication issued at stated, more or less regular, intervals.Postal Service: The functions and activities carried out by the U.S. Postal Service, foreign postal services, and private postal services such as Federal Express.Internet: A loose confederation of computer communication networks around the world. The networks that make up the Internet are connected through several backbone networks. The Internet grew out of the US Government ARPAnet project and was designed to facilitate information exchange.Mutation: Any detectable and heritable change in the genetic material that causes a change in the GENOTYPE and which is transmitted to daughter cells and to succeeding generations.18-Hydroxydesoxycorticosterone: An analog of desoxycorticosterone which is substituted by a hydroxyl group at the C-18 position.Mineralocorticoids: A group of CORTICOSTEROIDS primarily associated with water and electrolyte balance. This is accomplished through the effect on ION TRANSPORT in renal tubules, resulting in retention of sodium and loss of potassium. Mineralocorticoid secretion is itself regulated by PLASMA VOLUME, serum potassium, and ANGIOTENSIN II.Aldosterone Synthase: A mitochondrial cytochrome P450 enzyme that catalyzes the 18-hydroxylation of steroids in the presence of molecular oxygen and NADPH-specific flavoprotein. This enzyme, encoded by CYP11B2 gene, is important in the conversion of CORTICOSTERONE to 18-hydroxycorticosterone and the subsequent conversion to ALDOSTERONE.Blood Pressure Determination: Techniques for measuring blood pressure.Blood Pressure Monitoring, Ambulatory: Method in which repeated blood pressure readings are made while the patient undergoes normal daily activities. It allows quantitative analysis of the high blood pressure load over time, can help distinguish between types of HYPERTENSION, and can assess the effectiveness of antihypertensive therapy.Hypertension, Pulmonary: Increased VASCULAR RESISTANCE in the PULMONARY CIRCULATION, usually secondary to HEART DISEASES or LUNG DISEASES.History, 19th Century: Time period from 1801 through 1900 of the common era.Research Support, U.S. Gov't, Non-P.H.S.Research Support, U.S. Gov't, P.H.S.Research Support, Non-U.S. Gov'tResearch Support, U.S. GovernmentResearch Support, American Recovery and Reinvestment ActResearch Support, N.I.H., ExtramuralResearch Support, N.I.H., Intramural