A tribute to the late Hans W. Kosterlitz: ploughing the lone furrow

Hans Kosterlitz was a quiet, rather modest man, who was greatly respected, both as a scientist and as a person of real courage, honour, judgement, polite manners, and inflexible integrity of conduct and consistency of principle. His deep sense of social responsibility and his concern about making a worthwhile contribution for the benefit of mankind were reflected in his choice of research topics, in a career spanning more than 65 years. His major research interests were also exceptionally wide ranging, in terms of both subject matter and methodology. His first focus was the biochemistry of carbohydrate metabolism in diabetes mellitus and influence of dietary protein intake on the liver, then the physiology and pharmacology of enteric reflexes. It is his pioneering work on pharmacology of the narcotic analgesics and multiple opioid receptors and his illuminating concept, and subsequent discovery (in his eighth decade of life), of the occurrence of endogenous opioid peptides with which his name will be forever most closely linked. His infectious enthusiasm and zest for life made a lasting impression on everyone who met him, no matter how briefly. He was an inspiring teacher with a particular rapport with young scientists.