Renin is an enzyme produced in the kidney and is involved in the pathogenesis of hypertension. It stimulates the mechanism that increases blood pressure. Renin is located in the juxtaglomerular region of the kidney. It hydrolyses (breaks down) angiotensinogen secreted from the liver into angiotensin I, and to Angiotensin II which increase blood pressure. Angiotensin II, the most effective vasoactive peptide. It increases the contraction of the smooth muscles of the blood vessels of heart and leads to more effective pumping potential. This increases blood pressure. Angiotensin II also acts on the adrenal glands and induces the secretion of aldosterone, thereby, stimulating epithelial cells in the distal tubules of the kidneys thus, increases the reabsorption of sodium, and raising blood pressure. This mechanism is called the Renin-Angiotensin and Aldosterone system. Renin should not be confused with the enzyme Rennin (Chymosin) produced in the stomach to coagulate milk.
Interpretation:Renin inhibitors are used in the treatment of hypertension. This is usually decided after measurement of plasma renin activity (PRA). PRA may also be elevated in some tumours. Plasma Renin measurements may be investigated with plasma Aldosterone concentrations as the PAC/PRA ratio. High renin with normal aldosterone may indicate salt intolerance. Low renin and high aldosterone may mean that the adrenal glands are not functioning normally. If both are high, this may indicate a problem with the kidney functions. Renin and aldosterone are highest in the morning (circadian rhythm) and also give different results according to the. Therefore, these details should be noted by the laboratory, or the doctor should order the tests by informing the preferred options.
Sample: Arm venous blood. Nonfasting
Working day: friday
Result Time: Next day at 6 PM
