first messenger

American  

noun

Biochemistry.

1. a hormone that triggers a biochemical reaction at a site removed from its release.

---

Etymology

Origin of first messenger

First recorded in 1975–80

Example Sentences

“This,” he said, gesturing at the air above their heads, “is an object called 1I/2017 U1. Also known as ‘Oumuamua, which is a Hawaiian word meaning ‘first messenger.’

From The Verge

In this process, scientists refer to a “first messenger,” which arrives at the cell from outside, often as a hormone.

From Washington Post

The first messenger’s arrival at the outer wall of the cell eventually causes production within the cell of a “second messenger,” which prompts the cell to act.

From Washington Post

Activated by the arrival of the first messenger, it goes on to activate the production of the second.

From Washington Post

A first messenger of storm passed darkly over the sky, leaving the way clear again.

From Project Gutenberg