The two intrinsic mechanism which provide autoregulation of Glomerular Filtration Rate are :
(a) Myogenic Mechanism : An increase in blood pressure, tends to stretch the afferent arteriole which increases the blood flow to the glomerulus. When the wall of the arteriole contracts, the diameter of the afferent arteriole is reduced that increases the flow of blood.
(b) Juxta glomerular Mechanism : JGA cells secrete
enzymes like renin that modulate blood pressure and thus renal blood flow. This regulates Glomerular Filtration Rate.