Ultrastructure of turkey hepatocytes.

Abstract

Hepatocytes of normal male and female turkey livers perfused in situ with a fixative containing 4% glutaraldehyde in 0.05 M phosphate buffer (pH 7.4) were examined by electron microscopy. The hepatocytes, arranged in two-cell-layered plates, were polygonal and had three spatially different surfaces. The vascular surface was formed by microvilli, which at times projected into the sinusoids past the space of Disse. The interhepatocytic surfaces were closely applied and contained an occasional gap junction. The biliary surface participated in bile canaliculus formation and had short, regular microvilli. Tight junctions and adherens junctions were close to the canalicular lumen. The hepatocyte nucleus was located towards the vascular pole. The cytoplasm of hepatocytes of the females had many lipid droplets. The pleomorphic mitochondria, with relatively electron dense matrices were surrounded by one or, rarely, two profiles of flattened rER. Golgi complex was often observed in the vicinity of the nucleus, whereas the centrioles were located in the pericanalicular area of the biliary pole, which was rich in microtubules. These microtubules were extremely long, at times covering a substantial distance between the Golgi complex and bile canaliculi; microtubules occasionally formed bundles near the biliary pole. Small vesicles in close proximity of the microtubules were frequently observed. The spatial relationship between Golgi complex, microtubules, vesicles, and centrioles at the biliary pole of the hepatocyte appears to support the concept that the bile secretory mechanism in avian hepatocytes may involve a centrioles-microtubules-vesicles-Golgi complex system.