Angiotensin II is a potent vaso-active peptide that causes blood vessels to constrict, resulting in increased blood pressure. Angiotensin II also stimulates the secretion of the hormone aldosterone from the adrenal cortex. Aldosterone causes the tubules of the kidneys to increase the reabsorption of sodium and water into the blood.
The most reliable record of a Blue Shark at speed is 24.5 miles (39.4 kilometres) per hour for a 6.5-foot- (2-metre-) long individual. The Shortfin Mako (Isurus oxyrinchus) is probably the champion speedster among sharks.
Current consensus among shark scientists is that the top swimming speed of the Great White is at least 25 miles (40 kilometres) per hour. My own rough, back-of-the-envelope-type calculations - using several methods - suggest that the White Shark may achieve burst speeds of 35 miles (56 kilometres) per hour or more.