1. The anabolic agent Trienbolone acetate (3-oxo-17-β-hydroxy-4,9,11-estratriene acetate) given subcutaneously to female rats increased their growth rate compared with untreated controls (P < 0.001).
2. The compound had little androgenic activity.
3. The fractional synthetic and fractional degradative rates of the mixed muscle proteins were smaller in the treated rats than in the control rats.