A hormone, such as insulin or estrogen, is a substance released
by an organ or tissue that controls the activity of organs or
cells in another part of the body. The organs or glands that
release hormones are part of the endocrine system. Hormones may
also be taken as medicines, such as birth control pills or
estrogen replacement therapy. Last Revised: May 6, 2010 Author:
Healthwise Staff Medical Review: Sarah Anne Marshall, MD -
Family Medicine & Adam Husney, MD - Family Medicine & Kirtly
Jones, MD - Obstetrics and Gynecology To learn more visit
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