IL-6, or interleukin-6, is a chemical messenger involved in the destructive immune responses at the heart of arthritis.

Hormones travel throughout the body and act as chemical messengers.

These chemical messengers are transported outside of the body and result in a direct developmental effect on hormone levels or behavioral change.

These medications act in the brain on a chemical messenger called serotonin.

Kirk thought his original guess that the wormlike things were chemical messengers was probably right.

Hormones are chemical messengers that trigger many different processes, including growth and energy production.

In recent years, scientists have learned how to manipulate those chemical messengers to change the way they interact with the brain's signals.

A chemical messenger is any compound that serves to transmit a message.

IL-5 is a chemical messenger in the immune system that stimulates the growth of eosinophils.

Serotonin is a chemical messenger active between neurons, and it has a powerful effect on mood.