Insulin-like growth factor-I and insulin-like growth factor-II induce c-fos in mouse osteoblastic cells.
We investigated the expression of c-fos in mouse osteoblast-like cultures treated with insulin-like growth factor (IGF)-I and IGF-II. The IGFs are present in bone, are produced by osteoblast-like cells in culture, and stimulate osteoblast cell proliferation. Quiescent, subconfluent cultures of the clonal osteoblast-like mouse calvarial cell line, MC3T3-E1, were treated with 10 ng/ml of IGF-I or IGF-II. RNA was extracted at 0, 15, 30, 60, 120 and 240 minutes, and c-fos messenger RNA (mRNA) was analyzed on Northern blots. Both IGFs transiently increased c-fos mRNA levels 25-28 fold at 15-30 min. To determine if c-fos induction was unique to the MC3T3-E1 cell line, effects of IGF-1 and IGF-II (3 ng/ml) were also tested in quiescent, serum-free primary mouse calvarial cells. Levels of c-fos mRNA were increased at 15 and 30 minutes (40-fold with IGF-I and 5-fold with IGF-II). These results indicate that IGF-I and IGF-II caused a rapid and transient induction of c-fos mRNA in murine osteoblasts.
Merriman
H L
HL
Department of Biochemistry, Loma Linda University, California.
La Tour
D
D
Linkhart
T A
TA
Mohan
S
S
Baylink
D J
DJ
Strong
D D
DD
D000818:Animals; D002478:Cells, Cultured; D015870:Gene Expression / Q000187:drug effects; D007334:Insulin-Like Growth Factor I / Q000494:pharmacology*; D007335:Insulin-Like Growth Factor II / Q000494:pharmacology*; D051379:Mice; D010006:Osteoblasts / Q000187:drug effects* / Q000378:metabolism; D011519:Proto-Oncogenes / Q000187:drug effects*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D013002:Somatomedins / Q000494:pharmacology*
D012333:RNA, Messenger; D013002:Somatomedins; D007334:Insulin-Like Growth Factor I; D007335:Insulin-Like Growth Factor II