Growth hormone and insulin-like growth factor I regulate collagen gene expression and extracellular collagen in cultures of avian skin fibroblasts.
Avian skin fibroblasts were isolated, cultured and incubated with [3H]proline for 24 h. The cells exported radiolabeled collagenase-digestible (CDP) and non-collagenase-digestible (NCDP) proteins into the medium. Human, bovine and avian growth hormone (GH) as well as insulin-like growth factor I (IGF-I) attenuated the appearance of [3H]CDP in the medium without affecting [3H]NCDP. The appearance of [3H]CDP was not affected by prolactin. The effects of GH and IGF-I were enhanced by increasing concentrations of fetal calf serum (FCS). A synergism was observed between GH and IGF-I in their effect on CDP. Each peptide, at an ineffective concentration, increased the sensitivity of the cells to the other peptide. Collagenase activity in the medium was enhanced by IGF-I, but not modified by GH, FCS, or by their interaction with IGF-I. GH and IGF-I inhibition of type I procollagen gene expression was demonstrated with the aid of probes containing sequences corresponding to the mRNAs for avian alpha I and alpha II chains. The results suggest that GH and IGF-I cooperate in regulating collagen synthesis, but collagen degradation is affected by IGF-I and not by GH.
Granot
I
I
Institute of Animal Science, Agricultural Research Organization, Volcani Center, Bet Dagan, Israel.
Halevy
O
O
Hurwitz
S
S
Pines
M
M
D000818:Animals; D002417:Cattle; D002478:Cells, Cultured; D002645:Chickens; D003094:Collagen / Q000096:biosynthesis / Q000235:genetics*; D005347:Fibroblasts; D005786:Gene Expression Regulation; D013006:Growth Hormone / Q000502:physiology*; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000502:physiology*; D003012:Microbial Collagenase / Q000378:metabolism; D011388:Prolactin / Q000502:physiology
D007334:Insulin-Like Growth Factor I; D011388:Prolactin; D013006:Growth Hormone; D003094:Collagen; D003012:Microbial Collagenase