Biologists have found a hormone in the liver that spurs the growth of insulin-secreting cells in the pancreas, a discovery they hope will lead to new treatments for diabetes.
A team led by Douglas Melton, co-director of the Harvard Stem Cell Institute in Cambridge, Massachusetts, identified the hormone, betatrophin, by inducing insulin resistance in mice using a peptide that binds to insulin receptors. That caused the animals' insulin-secreting pancreatic β cells to proliferate. The researchers then searched for genes that showed increased activity, zeroing in on one that they were able to link to betatrophin production.
Further experiments showed that 8-week-old mice injected with betatrophin showed showed an average 17-fold rise in the replication of their insulin-secreting pancreatic β cells, the researchers report in Cell1. Betatrophin is also found in the human liver, the team says.
“It’s rare that one discovers a new hormone, and this one is interesting because it’s so specific,” says Melton. “It works only on β cells and it’s so robust and so potent.”
Pancreatic β cells replicate rapidly during embryonic and neonatal stages in both mice and humans, but their growth falls off dramatically in adults. A decrease in the function of the cells late in life is the main cause of type 2 diabetes, a metabolic disorder that affects more than 300 million people worldwide. In the United States alone, the two forms of diabetes — type 2 and and type 1, which is caused by an autoimmune attack on pancreatic β cells — account for US$176 billion in direct medical costs each year...
(Excerpt) Read more at nature.com ...
