Anterior Pituitary–Hypothalamic Hormones (2)	

Isolation and chemical identification of hypothalamic factors with anterior pituitary-regulating properties has focused on extracts of hypothalamic tissues. Initially, the factors were known as ‘releasing factors’ after the first description in 1955 of corticotrophin-releasing factor (CRF), now known as corticotrophin-releasing hormone (CRH). The term ‘releasing factor’ was introduced by Saffran and Schally to describe a substance extracted from the neural lobe, which stimulated the release of adrenocorticotrophic hormone (ACTH) from pituitary fragments maintained in organ culture. Twenty-six years later, the chemical nature of this substance was elucidated by Vale and colleagues (1981).