Abstract
The in vivo response of bone to IGF-I infusion in a marrow ablation model and the effect of IGF-I on bone marrow stromal cells in vitro was evaluated. IGF-I (25 ng/day), infused directly into femur, stimulated the expression of alkaline phosphatase, procollagen ∝1 (I) and osteopontin mRNA, while osteocalcin mRNA was not affected. The dose dependency to IGF-I was bi-phasic, with stimulation at 25 and 50 ng but not at 150 ng/day. The effect of IGF-I was observed in the aged but not in the adult rat femur. However, the elevated mRNA levels in old bones with IGF-I treatment were still below those observed in adult bones. The effect of IGF-I was also examined in cultured stromal cells. IGF-I (50 ng/ml) stimulates the expression of alkaline phosphatase, procollagen ∝1 (I), osteopontin and osteocalcin mRNA in stromal cells from both adult and old rats. These results suggest that the lack of response of adult bone to IGF-I in vivo was not due to the impaired response of the stromal cells to IGF-I. Differences in the responses of stromal cells from adult and old animals were noted. In the presence of serum (10%), stromal cells from adult rats were stimulated to synthesize DNA at lower levels of IGF-I than stromal cells from old animals. Our results show that IGF-I can stimulate mRNA expression of osteoblast markers in vivo in aged rats in a marrow ablation model and enhance DNA synthesis and gene expression in cultured marrow stromal cells from old rats. Thus, it is possible that exogenous IGF-I could be beneficial in treating age-associated osteopenia.
| Original language | English |
|---|---|
| Pages (from-to) | 647-653 |
| Number of pages | 7 |
| Journal | Bone |
| Volume | 15 |
| Issue number | 6 |
| DOIs | |
| Publication status | Published - 1994 |
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Keywords
- Aging
- Femur
- Gene expression
- IGF-I
- Marrow ablation
- Stromal cells
ASJC Scopus subject areas
- Physiology
- Hematology
Cite this
In vivo and in vitro effects of insulin-like growth factor-I (IGF-I) on femoral mRNA expression in old rats. / Tanaka, H.; Quarto, R.; Williams, S.; Barnes, J.; Liang, C. T.
In: Bone, Vol. 15, No. 6, 1994, p. 647-653.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - In vivo and in vitro effects of insulin-like growth factor-I (IGF-I) on femoral mRNA expression in old rats
AU - Tanaka, H.
AU - Quarto, R.
AU - Williams, S.
AU - Barnes, J.
AU - Liang, C. T.
PY - 1994
Y1 - 1994
N2 - The in vivo response of bone to IGF-I infusion in a marrow ablation model and the effect of IGF-I on bone marrow stromal cells in vitro was evaluated. IGF-I (25 ng/day), infused directly into femur, stimulated the expression of alkaline phosphatase, procollagen ∝1 (I) and osteopontin mRNA, while osteocalcin mRNA was not affected. The dose dependency to IGF-I was bi-phasic, with stimulation at 25 and 50 ng but not at 150 ng/day. The effect of IGF-I was observed in the aged but not in the adult rat femur. However, the elevated mRNA levels in old bones with IGF-I treatment were still below those observed in adult bones. The effect of IGF-I was also examined in cultured stromal cells. IGF-I (50 ng/ml) stimulates the expression of alkaline phosphatase, procollagen ∝1 (I), osteopontin and osteocalcin mRNA in stromal cells from both adult and old rats. These results suggest that the lack of response of adult bone to IGF-I in vivo was not due to the impaired response of the stromal cells to IGF-I. Differences in the responses of stromal cells from adult and old animals were noted. In the presence of serum (10%), stromal cells from adult rats were stimulated to synthesize DNA at lower levels of IGF-I than stromal cells from old animals. Our results show that IGF-I can stimulate mRNA expression of osteoblast markers in vivo in aged rats in a marrow ablation model and enhance DNA synthesis and gene expression in cultured marrow stromal cells from old rats. Thus, it is possible that exogenous IGF-I could be beneficial in treating age-associated osteopenia.
AB - The in vivo response of bone to IGF-I infusion in a marrow ablation model and the effect of IGF-I on bone marrow stromal cells in vitro was evaluated. IGF-I (25 ng/day), infused directly into femur, stimulated the expression of alkaline phosphatase, procollagen ∝1 (I) and osteopontin mRNA, while osteocalcin mRNA was not affected. The dose dependency to IGF-I was bi-phasic, with stimulation at 25 and 50 ng but not at 150 ng/day. The effect of IGF-I was observed in the aged but not in the adult rat femur. However, the elevated mRNA levels in old bones with IGF-I treatment were still below those observed in adult bones. The effect of IGF-I was also examined in cultured stromal cells. IGF-I (50 ng/ml) stimulates the expression of alkaline phosphatase, procollagen ∝1 (I), osteopontin and osteocalcin mRNA in stromal cells from both adult and old rats. These results suggest that the lack of response of adult bone to IGF-I in vivo was not due to the impaired response of the stromal cells to IGF-I. Differences in the responses of stromal cells from adult and old animals were noted. In the presence of serum (10%), stromal cells from adult rats were stimulated to synthesize DNA at lower levels of IGF-I than stromal cells from old animals. Our results show that IGF-I can stimulate mRNA expression of osteoblast markers in vivo in aged rats in a marrow ablation model and enhance DNA synthesis and gene expression in cultured marrow stromal cells from old rats. Thus, it is possible that exogenous IGF-I could be beneficial in treating age-associated osteopenia.
KW - Aging
KW - Femur
KW - Gene expression
KW - IGF-I
KW - Marrow ablation
KW - Stromal cells
UR - http://www.scopus.com/inward/record.url?scp=0027959680&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0027959680&partnerID=8YFLogxK
U2 - 10.1016/8756-3282(94)90313-1
DO - 10.1016/8756-3282(94)90313-1
M3 - Article
C2 - 7873293
AN - SCOPUS:0027959680
VL - 15
SP - 647
EP - 653
JO - Bone
JF - Bone
SN - 8756-3282
IS - 6
ER -