Co-Authors:
Monsonego, E., Institute of Animal Science, Agricultural Research Organization, The Volcani Center, Bet Dagan, 50250, Israel
Halevy, O., Department of Animal Science, The Hebrew University of Jerusalem, Faculty of Agriculture, Rehovot, 76100, Israel
Gertler, A., Department of Biochemistry and Human Nutrition, The Hebrew University of Jerusalem, Faculty of Agriculture, Rehovot, 76100, Israel
Hurwitz, S., Institute of Animal Science, Agricultural Research Organization, The Volcani Center, Bet Dagan, 50250, Israel
Pines, M., Institute of Animal Science, Agricultural Research Organization, The Volcani Center, Bet Dagan, 50250, Israel
Abstract:
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. © 1995.