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.
Most large sharks are cold-blooded and cruise at a leisurely 1.5 mph. Because most species fare poorly in captivity, the maximum swimming speed of a shark has seldom been measured. The Blue Shark is an open ocean glider, planing on wing-like pectoral fins and flattened belly.