The Probert Encyclopaedia of Medicine

KIDNEY

The kidneys are two, bean-shaped organs are located in the posterior of the abdomen. They generally are not thought of as endocrine organs.

The major function of the kidneys is the filtering toxins, wastes, ingested water, and mineral salts out of the bloodstream. However, the kidneys also serve a number of important endocrine functions.

They produce a substance called renin, which is an important enzyme in controlling blood pressure. When blood pressure falls, the kidneys release renin, which converts angiotensisnogen to the protein angiotensin I. This protein is then converted to angiotensin II,a protein which constricts blood vessels and thereby increases blood pressure. Angiotensis II also stimulates the release of aldosterone, a hormone that increases blood pressure.

The kidneys also produce the hormone erythropoietin, which stimulates bone marrow to produce red blood cells. Red bone marrow is responsible for the production of most blood cells- all red blood cells, platelets, and many white blood cells.
Research Kidney