Growth hormone inhibits differentiation of avian epiphyseal growth-plate chondrocytes.
The effect of chicken growth hormone (cGH) on the proliferation and differentiation of avian growth-plate chondrocyte was evaluated in culture. In culture, addition of ascorbic acid to the culture media caused cell differentiation. Treatment of proliferating chondrocytes with cGH caused a time-dependent increase in collagen type II gene expression together with a decrease in the appearance of osteopontin (OPN) in the medium. In addition, the ascorbic acid-dependent increase in alkaline phosphatase (AP) activity was inhibited by cGH. IGF-I, on the other hand, caused an increase in AP activity in the ascorbic acid-treated chondrocytes. In the presence of ascorbic acid, cGH did not affect collagen type II gene expression or the appearance of OPN in the medium. Proliferation of avian growth-plate chondrocytes, in contrast to mammalian chondrocytes, was not stimulated by GH alone, although the presence of cGH was essential for chondrocyte survival in long-term culture. cGH in combination with epidermal growth factor (EGF) stimulated cell proliferation. These results suggest that GH inhibits differentiation in avian growth-plate chondrocytes, thereby sustaining their proliferative state and maintaining their sensitivity to growth factors such as EGF.
Monsonego
E
E
Institute of Animal Science, Volcani Center, Bet Dagan, Israel.
Halevy
O
O
Gertler
A
A
Hurwitz
S
S
Pines
M
M
D000469:Alkaline Phosphatase / Q000378:metabolism; D000818:Animals; D001205:Ascorbic Acid / Q000494:pharmacology; D001846:Bone Development / Q000187:drug effects / Q000235:genetics; D002454:Cell Differentiation / Q000187:drug effects; D002478:Cells, Cultured; D002645:Chickens; D003094:Collagen / Q000235:genetics; D018507:Gene Expression Regulation, Developmental / Q000187:drug effects; D013006:Growth Hormone / Q000494:pharmacology*; D006132:Growth Plate / Q000166:cytology / Q000187:drug effects* / Q000254:growth & development; D053495:Osteopontin; D012795:Sialoglycoproteins / Q000378:metabolism
D012795:Sialoglycoproteins; D053495:Osteopontin; D013006:Growth Hormone; D003094:Collagen; D000469:Alkaline Phosphatase; D001205:Ascorbic Acid