Effects of estrogen on skeletal myoblast growth.

To determine the role of estrogen in skeletal muscle growth, we investigated estrogen receptor-mediated effects on proliferation in skeletal myoblasts. In L6, C2C12 and Sol8 myoblasts estrogen receptor was demonstrated by immunoblotting, immunofluorescence microscopy and transfection studies. Estrone induced a significant increase in myoblast growth whereas 17 beta-estradiol had no effect. Furthermore in L6-cells estrone (c-fos: 3.9-fold, egr-1: 4.6-fold) induced immediate-early gene induction significantly stronger than 17 beta-estradiol (c-fos: 1.7-fold, egr-1: 2.3-fold; p < 0.05). Skeletal myoblasts express functional estrogen receptors. Estrogens differ in the activation of skeletal myoblast growth and immediate-early gene induction.