Insulin resistance in cavefish as an adaptation to a nutrient-limited environment

Insulin resistance in cavefish as an adaptation to a nutrient-limited environment Nature 555, 7698 (2018). doi:10.1038/nature26136 Authors: Misty R. Riddle, Ariel C. Aspiras, Karin Gaudenz, Robert Peuß, Jenny Y. Sung, Brian Martineau, Megan Peavey, Andrew C. Box, Julius A. Tabin, Suzanne McGaugh, Richard Borowsky, Clifford J. Tabin & Nicolas Rohner Periodic food shortages are a major challenge faced by organisms in natural habitats. Cave-dwelling animals must withstand long periods of nutrient deprivation, as—in the absence of photosynthesis—caves depend on external energy sources such as seasonal floods. Here we show that cave-adapted populations of the Mexican tetra, Astyanax mexicanus, have dysregulated blood glucose homeostasis and are insulin-resistant compared to river-adapted populations. We found that multiple cave populations carry a mutation in the insulin receptor that leads to decreased insulin binding in vitro and contributes to hyperglycaemia. Hybrid fish from surface–cave crosses carrying this mutation weigh more than non-carriers, and zebrafish genetically engineered to carry the mutation have increased body weight and insulin resistance. Higher body weight may be advantageous in caves as a strategy to cope with an infrequent food supply. In humans, the identical mutation in the insulin receptor leads to a severe form of insulin resistance and reduced lifespan. However, cavefish have a similar lifespan to surface fish and ...
Source: Nature - Category: Research Authors: Tags: Letter Source Type: research