du Vigneaud, Vincent, 1901-78, American biochemist, b. Chicago. He was professor of biochemistry and head of the department at George Washington Univ. school of medicine (1932-38) and at Cornell Univ. medical college (from 1938). His researches involved the chemistry of insulin, protein, and sulfur compounds, and the syntheses of penicillin (1946) and the B-vitamin biotin (1942). He was awarded the 1955 Nobel Prize in Chemistry for his identification and synthesis of two pituitary hormones, oxytocin, used medicinally in obstetrics, and vasopressin, used to treat diabetes.