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Mol Cell Endocrinol. 2018 Sep 15;473:178-185. doi: 10.1016/j.mce.2018.01.017. Epub 2018 Feb 1.

Increased mitochondrial turnover in the skeletal muscle of fasted, castrated mice is related to the magnitude of autophagy activation and muscle atrophy.

Author information

1
Department of Nutrition, Food & Exercise Sciences, Florida State University, 600 W. College Ave, Tallahassee, FL 32306, United States.
2
Department of Nutrition, Food & Exercise Sciences, Florida State University, 600 W. College Ave, Tallahassee, FL 32306, United States. Electronic address: bsgordon@fsu.edu.

Abstract

Androgen-deficiency promotes muscle atrophy in part by increasing autophagy-mediated muscle protein breakdown during the fasted state, but factors contributing to this remain undefined. To identify novel factors, mice were subjected to sham or castration surgery. Seven-weeks post-surgery, mice were fasted overnight, refed for 30 min, and fasted another 4.5 h before sacrifice. BNIP3-mediated turnover of mitochondria was increased within the atrophied tibialis anterior (TA) of castrated mice and related to the magnitude of muscle atrophy and autophagy activation (i.e. decreased p62 protein content), thus linking turnover of potentially dysfunctional mitochondria with autophagy-mediated atrophy. Autophagy induction was likely facilitated by AMPK activation as a stress survival mechanism since phosphorylation of AMPK (Thr172), as well as the pro survival kinases Akt (Thr308) and (ERK1/2 Thr202/Tyr204), were increased by castration. Together, these data identify a novel relationship between mitochondrial turnover in the fasted state with autophagy activation and muscle atrophy following androgen depletion.

KEYWORDS:

Hypogonadism; Mitochondrial dysfunction; Mitophagy; Testosterone

PMID:
29378237
DOI:
10.1016/j.mce.2018.01.017

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