Concentric lamellar formations in hepatic parenchymal cells of carbon tetrachloride-treated rats

Regenerative parenchymal nodules developed in rat livers with advanced carbon tetrachloride-induced cirrhosis. Light microscopy revealed that these nodules contained groups of hepatic cells with intracytoplasmic, faintly laminated bodies (2-30 μ in diameter). Electron microscopy displayed these as concentric lamellar formations with myelin-like and fingerprint configurations. Both types consisted of multilayers of paired membranes, which were disposed concentrically about a core containing osmiophilic bodies. The peripheral membranes of the formations frequently communicated with the smooth-surfaced endoplasmic reticulum of contiguous, partially depleted glycogen areas; however, structural continuity with the Golgi complex, plasma membrane, or perinuclear membranes was not observed. Previously reported lamellar bodies of similar structure have been the subjects of fundamentally differing interpretations. Present evidence favors the view that the CCl₄-induced lamellar structures represent new formations of endoplasmic reticulum. It is possible that these formations are concerned with detoxification.