A substance, usually a peptide or steroid, produced by one tissue and conveyed by the bloodstream to another to effect physiological activity, such as growth or metabolism.

• 荷尔蒙一种物质,通常为肽或类固醇,由一组织产生,经由血液循环到达另一组织来影响生理活动,例如生长或新陈代谢。