Open AccessIncreased FNDC 5 is associated with insulin resistance in high fat‐fed mice
Author(s) -
Guilford Brianne L.,
Parson Jake C.,
Grote Caleb W.,
Vick Stephanie N.,
Ryals Janelle M.,
Wright Douglas E.
Publication year - 2017
Publication title -
physiological reports
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.918
H-Index - 39
ISSN - 2051-817X
DOI - 10.14814/phy2.13319
Subject(s) - fndc5 , endocrinology , medicine , insulin resistance , adipose tissue , white adipose tissue , thermogenesis , skeletal muscle , brown adipose tissue , insulin , biology , biochemistry , fibronectin , extracellular matrix
FNDC 5/irisin, has recently been identified as a novel protein that stimulates the “browning” of white adipose by inducing thermogenesis via increased uncoupling protein 1 ( UCP 1). We tested the hypothesis that high fat diet‐induced prediabetic mice would exhibit increased FNDC 5 and this effect would be attenuated by chronic exercise. C57 BL /6 mice were randomized into three groups for the 4 week intervention: Standard diet (Std, n = 12), High fat diet ( HF , n = 14), or High fat diet and free access to a running wheel ( HFEX , n = 14). Body weight, glucose, insulin, and the homeostatic model assessment of insulin resistance ( HOMA ‐ IR ) were greater in HF compared to Std and HFEX after the 4 week intervention. In support of our hypothesis, FNDC 5 was higher in HF in both skeletal muscle and adipose compared to Std and was lower in adipose only in HFEX compared to HF mice. Following the same pattern, PGC ‐1 α was significantly higher in HF compared to Std in skeletal muscle and significantly lower in HFEX compared to HF in adipose. UCP 1 was significantly lower in HFEX versus Std (in skeletal muscle) and versus HF (in adipose). HOMA ‐ IR was significantly correlated with FNDC 5 protein levels in adipose. Increased FNDC 5 in adipose and skeletal muscle may be a compensatory mechanism to offset high fat diet‐induced weight gain and insulin resistance by increasing energy expenditure.