Sir William Stanley Peart FMedSci FRS[1] (31 March 1922[2] – 14 March 2019) was a British medical doctor and clinical researcher who was first to demonstrate the release of noradrenaline after the stimulation of sympathetic nerves.

[3] Peart was the son of footballer and Fulham Football Club manager John George Peart and Margaret Joan (née Fraser).

[6] Peart's main research interest lay in renal medicine and in particular, a hormone system that regulates blood pressure and water called the renin–angiotensin system.

He was the first to purify the peptide hormone angiotensin and determine its structure.

He later isolated the enzyme renin — which catalyses the production of angiotensin — and carried out work to investigate the control of its release in the body.

Peart is also acknowledged as being the driving force behind the development of the renal transplant programme at St Mary's Hospital in Paddington, London.

He was also a trustee of the Wellcome Trust, where he headed their first clinical panel.

[3] Peart was elected a Fellow of the Royal Society (FRS) in 1969.

[7] He was awarded the Buchanan Medal of the Royal Society in 2000 "for his contribution to the foundations of understanding of the renin angiotensin system in particular through his seminal work on the isolation and determination of the structure of angiotensin, purification of renin, and subsequent studies on the control of renin release".

[8] In 1947,[9] Peart married Peggy Parkes, a nurse at St Mary's Hospital.