Du Vigneaud, d$uY vēn'yō, Vincent (1901-1978), a United States biochemist. He received the 1955 Nobel Prize in chemistry for his isolation and synthesis of oxytocin, a hormone important in childbirth, and vasopressin, a hormone that regulates blood pressure. He also played an important role in the synthesis of penicillin. Du Vigneaud was born in Chicago and attended the University of Illinois and the University of Rochester (Ph.D., 1927). He taught at George Washington University and later at Cornell University.