TY - JOUR
T1 - Insulin-like growth factor-I is required to maintain muscle volume in adult mice
AU - Nakamura, Satoshi
AU - Sato, Yuiko
AU - Kobayashi, Tami
AU - Oike, Takatsugu
AU - Kaneko, Yosuke
AU - Miyamoto, Kana
AU - Funayama, Atsushi
AU - Oya, Akihito
AU - Nishiwaki, Toru
AU - Matsumoto, Morio
AU - Nakamura, Masaya
AU - Kanaji, Arihiko
AU - Miyamoto, Takeshi
N1 - Publisher Copyright:
© 2018, The Japanese Society for Bone and Mineral Research and Springer Japan KK, part of Springer Nature.
PY - 2019/7/16
Y1 - 2019/7/16
N2 - 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.
AB - 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.
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U2 - 10.1007/s00774-018-0964-6
DO - 10.1007/s00774-018-0964-6
M3 - Article
C2 - 30324536
AN - SCOPUS:85055497738
SN - 0914-8779
VL - 37
SP - 627
EP - 635
JO - Journal of Bone and Mineral Metabolism
JF - Journal of Bone and Mineral Metabolism
IS - 4
ER -
