Faculty Opinions recommendation of Insulin resistance in cavefish as an adaptation to a nutrient-limited environment.
Year: 2018
Type: peer-review
Abstract: Periodic food shortages are a major challenge faced by organisms in natural habitats.Cavedwelling animals must withstand long periods of nutrient deprivation, as-in the absence of photosynthesis-caves depend on external energy sources such as seasonal floods 1 .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 do not accumulate the advanced glycation end-products in the blood that are typically associated with the progression of diabetes-associated pathologies.Our findings suggest that diminished insulin signalling is beneficial in a nutrient-limited environment and that cavefish may have acquired compensatory mechanisms that enable them to circumvent the typical negative effects associated with failure to regulate blood glucose levels.
Author: Malcolm Maden
Institution: University of Florida
Language: English
Subfield: Paleontology
Field: Earth and Planetary Sciences
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W4240266901