Hirudin Hirudin Hirudin is a naturally occurring peptide in the salivary glands of blood-sucking leeches (such as "Hirudo medicinalis") that has a blood anticoagulant property. This is fundamental for the leeches’ alimentary habit of hematophagy, since it keeps the blood flowing after the initial phlebotomy performed by the worm on the host’s skin. During his years in Birmingham and Edinburgh, John Berry Haycraft had been actively engaged in research and published papers on the coagulation of blood, and in 1884, he discovered that the leech secreted a powerful anticoagulant, which he named hirudin, although it was not isolated until the 1950s,
Renin inhibitor normal conditions, stimulation of the RAAS occurs in response to threats that compromise blood pressure stability, such as hypotension, blood loss and excessive loss of sodium and water. Blood pressure depends on total peripheral resistance and cardiac output. The highly selective aspartic protease renin is secreted from the juxtaglomerular apparatus, which is the only source of active renin, although its precursor, prorenin, can be secreted by other tissues, such as the salivary glands, brain, heart and blood vessels. Renin is a circulating enzyme that acts on a circulating peptide, angiotensinogen. Renin cleaves the peptide at the Leu10–Val11 bond, and this