Polar bears experience skeletal muscle atrophy in response to food deprivation and reduced activity in winter and summer.

ABSTRACT: When reducing activity and using stored energy during seasonal food shortages, animals risk degradation of skeletal muscles, although some species avoid or minimize the resulting atrophy while experiencing these conditions during hibernation. Polar bears may be food deprived and relatively inactive during winter (when pregnant females hibernate and hunting success declines for other demographic groups) as well as summer (when sea ice retreats from key foraging habitats). We investigated muscle atrophy in samples of biceps femoris collected from free-ranging polar bears in the Southern Beaufort Sea (SBS) throughout their annual cycle. Atrophy was most pronounced in April-May as a result of food deprivation during the previous winter, with muscles exhibiting reduced protein concentration, in

SUBMITTER: Whiteman JP 

PROVIDER: S-EPMC5550809 | biostudies-literature | 2017

REPOSITORIES: biostudies-literature