Adolf Butenandt (1903-1995), German biochemist. He is best known for his work on isolating and identifying sex hormones. In 1929, he isolated the female hormone oestrone. In 1931, Butenandt then isolated the male hormone androsterone and found that it was a derivative of cholesterol. He synthesised another male hormone, testosterone, in 1934. In the same year, he also isolated the female hormone, progesterone. Butenandt was awarded the 1939 Nobel prize in Chemistry but was forbidden by the Nazi German government. He later accepted the award in 1949.