Angiotensin-2 mainly act by -

Angiotensin-II has several effects that make the kidneys retain salt and water, It constricts the efferent aerioles, which has two effects on peritubular capillary dynamics that increase sodium and water reabsorption. Efferent aeriolar constriction reduces peritubular capillary hydrostatic pressure, which increases net tubular reabsorption, especially from the proximal tubules. Efferent aeriolar constriction, by reducing renal blood flow, raises filtration fraction in the glomerulus and increases the concentration of proteins and the colloid osmotic pressure in peritubular capillaries, This mechanism increases the resorptive force at the peritubular capillaries and raises tubular reabsorption of sodium and water.