Substance formed in one organ or part of the body and carried in the blood to another organ or part where it selectively alters functional activity.
Source:
PAC, 2016, 88, 713. 'Glossary of terms used in developmental and reproductive toxicology (IUPAC Recommendations 2016)' on page 765 (https://doi.org/10.1515/pac-2015-1202)