There is an auto regulatory mechanism present in the kidney to regulate the glomerular filtration rate. This mechanism is carried out by juxta glomerular apparatus (JGA) which is a special sensitive region formed by cellular modification of the distal convoluted tubule and the different arteriole at the location of their contact. A fall in the GFR will activate the JG cells to release renin which converts the angiotensinogen in blood to angiotensin I and later into angiotensin II. The angiotensin II is a powerful vaso constrictor which increases the glomerular blood pressure and there by increase the GFR. The Angiotensin II also activates the adrenal cortex to release aldosteron which causes the reabsorption of Na⁺ and water from the distal parts of the tubule. This also results in the increase in blood pressure and GFR.