Acclaimed by his peers as "a brilliant mind" and internationally recognized for his work in kidney physiology, Dr. Harald Sonnenberg will receive The Kidney Foundation of Canada's prestigious Medal for Research Excellence on November 21 in Toronto.

A graduate of the University of Alberta, Dr. Sonnenberg went on to obtain his Ph.D. from the Free University of Berlin in 1964. He joined the Department of Physiology at the University of Toronto in 1967 and remained there until his retirement in 1998.

During his long and illustrious career spanning over 40 years, enormous strides have been made in the scientific understanding of kidney physiology. Dr. Sonnenberg's seminal work in the area of sodium handling by the kidney - one of its most important functions - earned him international renown. He perfected a novel technique - the microcatheterization of a tiny segment of the kidney's filtering units called the medullary collecting duct (MCD) - in order to prove his theory that the MCD was the key to controlling sodium reabsorption. Previously, scientists had been focusing on other areas of the kidney where they believed this complex process took place.

Shortly afterwards, Dr. Sonnenberg was recruited by a hypertension research team led by Dr. Aldolfo de Bold, to examine how the kidneys' regulation of sodium affected blood pressure control. Their ground-breaking work was a Canadian research triumph and in 1986 the team was awarded the Gairdner International Award for Medical Research for the discovery and characterization of atrial natriuretic factor, an important hormone controlling salt and water metabolism.

In addition to his research contributions, Dr. Sonnenberg has played an important role in the clinical teaching of renal physiology and his articles have been published in several high impact journals. He is widely regarded as the catalyst that transformed Toronto into an international centre of excellence in renal physiology.