//Almost all work on diabetes, whether clinical, experimental or theoretical, concentrates on insulin and glucose and the interactions between them. Less attention is paid to the other major player in the system, glucagon. My co-workers at Stellenbosch University in South Africa and I have pointed out that the glucagon-producing alpha cells are not very sensitive to the glucose concentration [1]. They need some other signal to tell them when to stop secreting glucagon, and this is almost certainly from the nearby beta cells. We know there is communication among beta cells and that this communication is impaired in diabetics. If the alpha cells depend on signals from the beta cells, then if communication is blocked, they will continue to secrete glucagon when the glucose level is too high. Even if the fat cells are responding normally to insulin and taking up glucose at the appropriate rate, the glucose level will fall more slowly than it should because the liver is being stimulated to release more into the blood stream. The likely cause of impaired communication in the pancreas is the build up of amyloid fibrils. These are observed in autopsies of people who had type 2 diabetes but they have always been thought of as a consequence of diabetes, not a cause [1].//
Posted on: Mon, 21 Jul 2014 20:37:39 +0000
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