Melatonin
Melatonin is a hormone secreted by the pineal gland (an endocrine gland in the human body).
The hormone melatonin is important for setting and maintaining the body's biological clock - that is, regulating the day/night rhythm based on periods of light/darkness.
- Melatonin is produced by the pineal gland in darkness but not in bright light.
- Melatonin receptors in the brain react to this hormone and synchronize the body to the 24 hour day/night rhythm, thus informing the brain when it is day and when it is night.
- Melatonin is derived from seratonin - with which it works to regulate the sleep cycle.
Melatonin levels are higher in children than in adults, and decline with age into adulthood.
Seasonal Affective Disorder (SAD), a form of depression that affects some people during the winter months when the length of days is short, it thought to be partly due to overproduction of melatonin.
See also: What is a Hormone ?
For further general information including the locations of the endocrine glands, see the Endocrine Glands of the Human Body.
More about the Endocrine System
- Introduction to the Endocrine System
- What is a hormone ?
- Water Soluble Hormones vs Fat Soluble Hormones
- Triggers for Hormone Release
- Hormone Regulation Feedback Mechanism
- Major Glands of the Endocrine System
- The Pituitary Gland
- The Adrenal Glands
- Non-endocrine tissues that release hormones
- Conditions of the Endocrine System
- Diabetes
