Dose Dependent Effects of Corticosterone of Proliferation and Differentiation in Chick Myoblasts.

Abstract

The effect of corticosterone (CTC) at low and high concentrations on proliferation and differentiation was studied in chick myoblasts. Chick myoblasts were incubated with low (3ng/ml) and high (30ng/ml) levels of CTC. DNA content and creatine kinase activity were measured as indices of cell proliferation and differentiation, respectively, at 2, 4 and 6 days of incubation. DNA content was increased by CTC at low level regardless of the incubation time. Creatine kinase activity was decreased by the low level of CTC. On the other hand, the high level of CTC increased creatine kinase activity on day 2 and 4 but not on day 6. These results indicate that a low level of CTC stimulates proliferation but inhibits differentiation, while a high level of CTC stimulates differentiation but not proliferation in chick myoblasts. Furthermore, it is indicated that a long term treatment with high level of CTC also inhibits differentiation.