Table 1.

Magnitude of skeletal changes in mice lacking total, local bone, liver-derived, and endocrine IGF-I actions

	Total IGF-I KOa	Local bone IGF-I KO		Liver IGF-I KOd	Endocrine IGF-I KOe
		Chondrocyte IGF-I KOb	Osteoblast IGF-I KOc
Serum IGF-I	100% ↓	Normal	Normal	75% ↓	97.5% ↓
Length	40% ↓	7% ↓	14% ↓	Normal	6% ↓
Cortical bone width	38% ↓	7% ↓	20% ↓	9% ↓	18% ↓
Cortical vBMD	30% ↓	4% ↓	5% ↓	7% ↓	11% ↓
Trabecular BV/TV	55% ↑	ND	20% ↓f	10–20% ↓	8% ↓f
Bone formation rate	70% ↓	ND	48% ↓	ND	ND
Mineral apposition rate	40% ↓	ND	38% ↓	ND	ND

ND, Not determined; vBMD, volumetric BMD; BV/TV, bone volume/ total volume. 

^aData for length, bone width, and cortical vBMD were derived from Mohan et al. (50), whereas data for trabecular BV/TV, bone formation rate, and mineral apposition rate were derived from Bikle et al. (153). 

^bData for chondrocyte IGF-I KO mice were derived from Govoni et al. (52). 

^cData for osteoblast IGF-I KO mice were derived from Govoni et al. (53). 

^dData for liver-specific IGF-I KO are summaries of the main findings from several studies using mice with liver-specific IGF-I KO (11,12,58,61,62,155). 

^eData for length and bone width of endocrine IGF-I KO were derived from triple KO mice lacking liver-derived IGF-I, total IGFBP-3, and total ALS (61), whereas data for cortical vBMD and trabecular BV/TV were derived from double KO mice lacking liver-derived IGF-I and ALS (62). 

^fNot significant.