Table 1.

Changes in IGF-I, IGF-IR, and IGFBP mRNA expression in TA muscles (expressed as fold difference compared with the PBS-injected/noncasted TA muscle)

	Noncasted		2wk Immob		1wk Reamb		3wk Reamb
Gene	PBS	IGF-I	PBS	IGF-I	PBS	IGF-I	PBS	IGF-I
IGF-I	1.0 ± 0.1	185.4 ± 21.6*	0.4 ± 0.1	176.9 ± 9.9*	2.8 ± 0.9†	171 ± 48.0*	1.2 ± 0.2	98 ± 24.4*†
IGF-IR	1.0 ± 0.1	1.1 ± 0.1	1.6 ± 0.2†	1.8 ± 0.03†	0.5 ± 0.08†	0.5 ± 0.1†	0.8 ± 0.07	0.8 ± 0.1
IGFBP-3	1.0 ± 0.1	1.3 ± 0.2	1.8 ± 0.4†	2.2 ± 0.3†	0.9 ± 0.1	0.8 ± 0.1	1.1 ± 0.1	1.2 ± 0.2
IGFBP-4	1.0 ± 0.1	1.4 ± 0.2	1.0 ± 0.1	1.3 ± 0.1	1.3 ± 0.4	1.6 ± 0.4	1.0 ± 0.1	1.2 ± 0.3
IGFBP-5	1.0 ± 0.1	1.7 ± 0.2*	0.2 ± 0.01†	0.3 ± 0.03*†	2.5 ± 0.4†	3.3 ± 0.08*†	1.0 ± 0.1	2.2 ± 0.08*

Values are means ± SE. TA, tibialis anterior; 2 wk Immob, 2 wk of cast immobilization; 1 wk Reamb, 1 wk of free cage reambulation; 3 wk Reamb, 3 wk of free cage reambulation; IGF-IR, IGF-I receptor; IGFBP, IGF-binding protein.

^*Significant difference within each loading time point between IGF-I-injected and PBS-injected muscles.

^†Value at this loading time point was significantly different from noncasted group in the same injection group. P < 0.05.