CONTROL MYOTUBES - C2C12 mouse myoblasts (American Type Culture Collection, Manassas, VA) were maintained in growth medium (DMEM supplemented with 10% Fetal Bovine serum, Invitrogen Corporation, Carlsbad, CA) in 5% CO2. Cells were plated at a density of 40-50% in 100mm dishes. When cells reached ~90% confluency 24 hours later, they were switched to differentiation media (DMEM containing 2% horse serum; GIBCO, Invitrogen Corporation, Carlsbad, CA) which was subsequently changed every 48 hours. All cells were allowed to differentiate for 4 days with feeding every two days (day 0, 2, and 4). Beginning at day 4, control cells were re-fed every 48 hours whereas experimental cells were not re-fed. After an additional 4 days (8 days post differentiation), cells were harvested and total RNA was isolated from control and "starved" (non re-fed cells) Keywords = skeletal muscle Keywords = atrophy