Researchers find link between melatonin, diabetes risk

By Stephen Feller

LUND, Sweden, May 13 (UPI) -- Researchers may have found why having a sleep disorder or working overnight is thought to increase risk for developing type 2 diabetes.
A genetic variation causes insulin-producing beta cells to be more sensitive to melatonin, affecting their ability to secrete insulin and throwing off the control of blood sugar, according to a study published in the journal Cell Metabolism.
Melatonin regulates the circadian rhythm, reacting to light and dark throughout the course of the day. The hormone increases, peaking at night, during sleep -- part of the reason it has been used as a drug for sleeping.
Previous research conducted by the same researchers at Lund University in 2009 showed a gene variant to melatonin receptor 1B increases risk for type 2 diabetes. The variant causes the level of the melatonin receptors in beta cells to increase, making them more sensitive to melatonin and stopping them from secreting insulin.
"A third of all people carry this specific gene variant," Hindrik Mulder, a professor at Lund University, said in a press release. "Our results show that the effect of melatonin is stronger in them. We believe that this explains their increased risk of developing type 2 diabetes."
For the study, researchers recruited 23 healthy carriers of the gene variant and 22 people without the variant, treating them with four milligrams of melatonin before bed for three months.
The researchers found insulin secretion was lower among participants with the genetic variation, and that blood glucose levels were higher among all participants after melatonin treatment -- but most significantly in those with the variation.
"There is still no scientific support for this theory, but it ought to be studied in the future, on the basis of our new findings," Mulder said.

http://www.upi.com/Health_News/2016/05/13/Researchers-find-link-between-melatonin-diabetes-risk/7081463162949/