Endorphins
All of the endorphins bind to the opioid receptors in the brain. Many of the analgesic (pain killer) drugs have a similar action in the brain. The main difference between the natural endorphins and the analgesic drugs is that natural endorphins are cleared from the blood very quickly. Endorphins are also involved in the release of sex hormones in the pituitary gland. Also, scientists think that acupuncture results in the release of more endorphins. Endorphins may have a role in obesity, diabetes and psychiatric diseases too.