Schack August Steenberg Krogh (November 15, 1874 - September 13, 1949) was a professor of zoophysiology at the University of Copenhagen 1916-1945. He contributed a number of fundamental discoveries within several fields of physiology.

In 1920 August Krogh was awarded the Nobel Prize in physiology and medicine for the discovery of the mechanism of regulation of the capillaries in skeletal muscle. Krogh was first to describe the adaptation of blood perfusion in muscle and other organs according to demands through opening and closing the arterioles and capillaries.

Krogh was a pioneer in comparative studies on animals. He wrote his thesis on the respiration through the skin and lungs in frogs: Respiratory Exchange of Animals, 1915. Later Krogh took on studies of water and electrolyte homeostasis of aquatic animals and he published the books: Osmotic Regulation (1939) and Comparative Physiology of Respiratory Mechanisms (1941). In addition Krogh contributed more than 200 research articles in international journals. He was a constructor of scientific instruments of which several had considerable practical importance, e.g. the spirometer and the apparatus for measuring basal metabolic rate.

Krogh brought insulin to Denmark shortly after its discovery in 1922 by Banting and Best in Toronto. Together with Hagedorn, Krogh made decisive contributions to establishing a Danish production of insulin by ethanol extraction of the hormone from the pancreatic glands of pigs.

Much of Krogh's work was carried out in collaboration with his wife, Marie Krogh (1874-1943), a renowned scientist in her own right.

In 1910 August Krogh founded the first laboratory for animal physiology (zoophysiology) at the University of Copenhagen. It was located in a small townhouse in central Copenhagen (at Ny Vestergade 11). The laboratory was considerably enlarged in 1928, when it moved to a new building at Juliane Maries Vej 28-32, financed by the Rockefeller Foundation. The building also gave place to the institutes of medical physiology and biophysics, and to the institute for the theory of gymnastics (exercise physiology). Today, the disciplines of animal physiology, exercise physiology, and some of the biochemical subdisciplines under the Faculty of Science are based at the August Krogh Institute, a building inaugurated in 1970.

(description from Copenhagen University)