Читать книгу Essential Endocrinology and Diabetes - Richard I. G. Holt - Страница 17

 The gland must secrete a substance (an ‘internal secretion’)

 Methods of detecting the secretion must be available

 The purified substance (the hormone) must be recoverable from gland extracts

 The hormone must be capable of isolation for its structure to be determined and for synthesis

To this could be added:

 The hormone must act on specific target cells via a receptor such that excess or deficiency causes a specific phenotype