renin
re·nin
R0151700 (rē′nĭn, rĕn′ĭn)renin
(ˈriːnɪn)re•nin
(ˈri nɪn)n.
Noun | 1. | renin - a proteolytic enzyme secreted by the kidneys; catalyzes the formation of angiotensin and thus affects blood pressure |
单词 | renin | |||
释义 | reninre·ninR0151700 (rē′nĭn, rĕn′ĭn)renin(ˈriːnɪn)re•nin(ˈri nɪn)n.
Reninrenin[′rēn·ən]Renina proteolytic enzyme in vertebrates and humans. It is produced by specialized cells in the arteriole walls of renal glomeruli, from where it passes into the blood and lymph. Renin is one of the enzymes in the renin-angiotensin system. It acts on the specific glycoprotein angiotensinogen by breaking the bond between two leucine radicals. The resultant inactive decapeptide (angiotensin I) is enzymatically converted into the active hormone angiotensin II (hypertensin, or angiotonin). Enzymes resembling renin are found in the uterus, placenta, salivary glands, brain, and the walls of certain major arteries. reninrenin[re´nin]Stimuli to the secretion of renin include sodium depletion, dehydration, serum albumin depletion, cirrhosis of the liver, cardiac failure, renal artery stenosis, and renal nerve stimulation. Whenever blood flow to the kidney diminishes, renin is secreted and angiotensin is formed. The angiotensin causes widespread vasoconstriction and elevation of blood pressure consequent to greatly increased total peripheral resistance. A second effect, the increased secretion of aldosterone, results in retention of salt and water by the kidneys and therefore increased extracellular fluid volume, cardiac output, and arterial pressure. Additionally, the angiotensin acts directly on the kidneys to cause salt and water retention, which causes a long-term increase in arterial blood pressure. ![]() re·nin(rē'nin), [MIM*179820]renin(rē′nĭn, rĕn′ĭn)reninPhysiology An aspartyl proteinase with one substrate, angiotensinogen, which is secreted primarily by the granular cells of the juxtaglomerular apparatus, as well as the brain and endothelial cells, in response to ↓ renal perfusion pressure or ↓ kallikrein; renin cleaves angiotensinogen to yield angiotensin I–a decapeptide, the precursor of angiotensin II–an octapeptide, and angiotensin III–a heptapeptide; the latter 2 are potent vasoconstrictors, and stimulate thirst and ↑ aldosterone production ↑ in Addison's disease, COPD, CRF hypersecretion, eclampsia–and preeclampsia, hyperthyroidism, cirrhosis, ↓ K+, ↓ salt diet, malignant HTN, pregnancy, renal failure, renovascular HTN, functional kidney tumors, drugs–eg, antihypertensives, diuretics, estrogens, OCs ↓ in Cushing syndrome, DM, essential HTN, hypothyroidism, high salt diet, drugs–eg, antihypertensives, levodopa, propranol. See Hypertension, Plasma renin activity.re·nin(rē'nin)Synonym(s): angiotensinogenase. reninAn enzyme produced by the kidney in conditions of abnormally low blood pressure. Renin catalyses the release of angiotensin I from a blood globulin angiotensinogen, and this, in turn, is converted to angiotensin II by a converting enzyme found in the lung. Angiotensin II causes the adrenal glands to secrete the hormone aldosterone which acts on the kidneys to reduce the loss of sodium in the urine. The increased blood sodium raises the blood pressure. See also ACE INHIBITORs.renina protein-splitting enzyme (sometimes called a hormone) secreted into the blood by the cells lining the efferent glomerular vessels of the kidney Renin combines with a protein from the liver to form ANGIOTENSIN which in turn stimulates the cortex of the ADRENAL GLAND to release ALDOSTERONE.Reninrenin
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