New Scientist
Image: jepoirrier
Too much insulin may be bad for our health, turning the received wisdom about diabetes and Alzheimer’s disease on its head. Mice genetically engineered so that their brains don’t respond to insulin live longer and are less likely than normal mice to develop age-related diseases similar to Alzheimer’s.
Insulin plays a key role in encouraging the uptake and storage of glucose by cells. Its effects on the brain are less clear, but previous studies suggested that the hormone may stave off age-related degeneration.
“Everybody says insulin is good for you. It keeps cells alive,” says Morris White of the Children’s Hospital in Boston. “But reviews are now starting to suggest that too much insulin can damage the brain and promote Alzheimer’s.”
Last week he and his colleagues published research supporting that theory. They genetically engineered mice so that their brains didn’t produce Irs2, a key insulin receptor usually expressed throughout the body. The mice could eat as much food as they wanted and by 2 months of age all had become overweight and glucose intolerant. Like overweight humans, the mice had more insulin in their blood, but remarkably, says White, they did not develop diabetes or the mouse equivalent of Alzheimer’s and lived on average 14 per cent longer than normal mice. Read more…
