Open AccessWhat Is a Hormone?
Author(s) -
L Stárka,
Michaela Dušková
Publication year - 2020
Publication title -
physiological research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.647
H-Index - 70
eISSN - 1802-9973
pISSN - 0862-8408
DOI - 10.33549/physiolres.934509
Subject(s) - hormone , autacoid , erythropoietin , secretion , peptide hormone , fibroblast growth factor , biology , endocrinology , medicine , receptor
Starling’s original definition of a hormone from 1905 was “a hormone is a substance produced by glands with internal secretion, which serve to carry signals through the blood to target organs”. Today, this definition is understood to be lacking, but newer definitions also do not encompass the entire meaning of hormones as specific carriers of information. One main problem is that there is no delineation between hormones and other signaling molecules such as cytokines, growth factors or autacoid compounds. It seems that a precise definition is not even possible, since some cytokines and growth factors, such as the cytokines erythropoietin, lipocalin-2 and asprosin or fibroblast growth factor 23, act as hormones under certain conditions.