(1924-) French-born US endocrinologist. He has isolated and identified various hormones, for which he received the 1977 Nobel Prize for Physiology or Medicine, together with his co-worker Andrew Schally (1926– ) and US physicist Rosalyn Yalow. Guillemin also discovered endorphins.
Guillemin was born in Dijon and educated there and at Lyon. He moved to the US 1953 and did most of his work at the Baylor College of Medicine, Houston, becoming professor 1963. In 1970 he joined the Salk Institute in La Jolla, California.
Guillemin found that the brain controls the pituitary gland by means of hormones produced by central neurons—the neurosecretory cells of the hypothalamus. He worked with Lithuanian refugee Schally 1957–62, and later their investigations were parallel. Between 1968 and 1973 they isolated and synthesized three hypothalamic hormones which regulate the secretion of the anterior pituitary gland.