According to the classical concept of Geoffrey Harris the pituitary gland is controlled by the brain by means of blood-borne chemical messengers produced by central neurons. The recent isolation and structural characterization of several such messengers by Roger Guillemin and Andrew Schally and their collaborators brought the final proof for this hypothesis. This also meant that the extensive knowledge collected in the field of neurobiology now became highly relevant for the endocrinologists. For this reason it was felt important to organize a symposium which brought together experts in the...