Insulin-like growth factor-I is required to maintain muscle volume in adult mice

Satoshi Nakamura, Yuiko Sato, Tami Kobayashi, Takatsugu Oike, Yosuke Kaneko, Kana Miyamoto, Atsushi Funayama, Akihito Oya, Toru Nishiwaki, Morio Matsumoto, Masaya Nakamura, Arihiko Kanaji, Takeshi Miyamoto

Research output: Contribution to journalArticlepeer-review

12 Citations (Scopus)


Insulin-like growth factor-I (IGF-I) is a peptide with diverse functions, among them regulation of embryonic development and bone homeostasis. Serum IGF-I levels decline in the elderly; however, IGF-I function in adults has not been clearly defined. Here, we show that IGF-I is required to maintain muscle mass in adults. We crossed Igf-I flox’d and Mx1 Cre mice to yield Mx1 Cre/Igf-Iflox/flox (IGF-I cKO) mice, and deleted Igf-I in adult mice by polyIpolyC injection. We demonstrate that, although serum IGF-I levels significantly decreased after polyIpolyC injection relative to (Igf-Iflox/flox) controls, serum glucose levels were unchanged. However, muscle mass decreased significantly after IGF-I down-regulation, while bone mass remained the same. In IGF-I cKO muscle, expression of anabolic factors such as Eif4e and p70S6K significantly decreased, while expression of catabolic factors MuRF1 and Atrogin-1 was normal and down-regulated, respectively, suggesting that observed muscle mass reduction was due to perturbed muscle metabolism. Our data demonstrate a specific role for IGF-I in maintaining muscle homeostasis in adults.

Original languageEnglish
Pages (from-to)627-635
Number of pages9
JournalJournal of Bone and Mineral Metabolism
Issue number4
Publication statusPublished - 2019 Jul 16


  • Adult
  • Aging
  • Insulin-like growth factor-I
  • Muscle wasting

ASJC Scopus subject areas

  • Endocrinology, Diabetes and Metabolism
  • Orthopedics and Sports Medicine
  • Endocrinology


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