Subterranean Fishes of the World

4072

2018

Evolution, Medecine and Public Health

1186-189

2018

Obesity induced insulin resistance is believed to be central to type 2 diabetes in humans. Recent work on Mexican cavefish, Astyanax mexicanus, has revealed a hyperglycemic phenotype that has some similarities with human type 2 diabetes, but important differences too. In cavefish, insulin resistance is the cause of obesity rather than an effect. Instead of developing diabetic complications, the hyperglycemic fish lead a healthier and longer life than their surface fish counterpart. In addition to fish, insulin resistance in hibernating bears, dolphins, horse, bonnet macaques and chimpanzees demonstrate that the relationship between diet, obesity, insulin sensitivity and diabetes is widely different in different species. Evolutionary hypotheses about type 2 diabetes should look beyond obesity to explain the differences in associations between diet, obesity, insulin resistance, hyperinsulinemia and hyperglycemia in different species.

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