(1905–83), Swedish physiologist; full name Ulf Svante von Euler ; son of Hans Euler-Chelpin. He was the first to discover a prostaglandin, which he isolated from semen. Euler also identified norepinephrine as the principal chemical neurotransmitter of the sympathetic nervous system. He shared the 1970 Nobel Prize for Physiology or Medicine with Bernard Katz (1911–2003) and Julius Axelrod (1912–2004).