Life Lines by Dr. Dolittle

Sponsored by the American Physiological Society

Extreme fasting

 

NES Pup

Image of Northern elephant seal pup By Chuck Abbe (originally posted to Flickr as Elephant seal pup), via Wikimedia Commons

Northern Elephant seals (Mirounga angustirostris) are pretty extreme animals, at least when it comes to fasting. Pups nurse for about 1 month, during which time they greatly increase their body fat. After nursing, they typically fast for up to 3 months.

A new study was designed to explore how their adipose (fat) tissue changes after this prolonged fast. Researchers at the University of California at Merced were able to identify nearly 100 genes that were altered by fasting. Many of the genes that were altered were known to encode for proteins involved in fat, carbohydrate and protein metabolism along with genes that encode for proteins involved in tissue remodeling during weight loss.

The hope is by understanding how Northern elephant seals regulate fat metabolism, we may be able to discover mechanisms involved in regulating energy balance in other mammals too.

Sources:

Ortiz RM, Wade CE, Ortiz CL. Effects of prolonged fasting on plasma cortisol and TH in postweaned northern elephant seal pups. American Journal of Physiology Regulatory Integrative Comparative Physiology. 280: R790–R795, 2001.

Martinez B, Khudyakov J, Rutherford K, Crocker DE, Gemmell N, Ortiz R. Adipose transcriptome analysis provides novel insights into molecular regulation of prolonged fasting in northern elephant seal pups. Physiological Genomics. 50(7):495-503 https://doi.org/10.1152/physiolgenomics.00002.2018

Categories: Comparative Physiology

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