Electron micrographs illustrating liver cells from control (A and D) fasten (B and D) and fed restricted (C and E) rats. Notice that hepatocytes from the fed restricted animal (F) exhibit electron-dense mitochondria (m) surrounded by abundant smooth endoplasmic reticulum (SER). N = cell nucleus, gl = glycogen, asterisks = lipid droplets, arrows = bile canaliculi. Lead-uranium staining. Scale bars = 2 μm in A-C; 0.2 μm in D-E. Representative images of 6 independent experimental observations.