Ultrastructure of the hepatocytes in a vertebrate liver without bile ducts
Youson, J.H.; Sidon, E.W.; Peek, W.D.; Shivers, R.R.
Journal of Anatomy 140: 143-158
1985
ISSN/ISBN: 0021-8782 PMID: 2999046 Document Number: 247185
Thin sections and freeze fracture replicas were used to study the structure of the hepatocytes of the parasitic adult lamprey (Petromyzon marinus). Despite the absence of bile ducts and bile canaliculi, the hepatocytes had some features which resemble those of cells in the livers of other vertebrates. Hepatocytes were characterized by large gap junctions, many cytoplasmic inclusions and large deposits of Fe. The latter was present throughout the cytoplasmic matrix and within large inclusion bodies which may have arisen through sequestration of parts of the cytoplasm by membrane isolation. There was no evidence for the involvement of hepatocytes in glucose metabolism but their fine structure reflected the production of bile products and the processing of lipoproteins. The accumulation of bile products within cytoplasmic inclusions resembled the situation resulting from biliary atresia or other cholestatic conditions in higher organisms. There was little folding of the plasma membrane facing the perivascular space (of Disse), perhaps indicating limited involvement of this surface in the transport of bile products. Nerve endings in close apposition to hepatocytes suggest possible nervous control or metabolic function or the presence of sensory receptors in lamprey liver.