Enzyme Histochemical and Ultrastructural Observations on the Liver of Teleost Fishes

Abstract

The liver of eight freshwater and marine teleost species originating from temperate and tropical waters, have been studied with histochemical methods and with the electron microscope. Marked species differences have been found in respect to enzyme activities, lipid and glycogen contents as well as to the ultrastructural characters of the hepatocytes. Alkaline phosphatase was found in the majority of species predominantly along the sinusoids and possibly also along the bile canaliculi. Cholin-esterase was found in the same localization as alkaline phosphatase, but was usually detected only in low concentrations. Lysosomal enzymes (E 600 resistent esterase, acid phosphatase, β-glucuronidase, β-glucosaminidase, β-galactosidase) were observed generally in moderate or weak, rarely also in strong concentrations. NADH- and NADPH-diaphorases are of strong or moderate intensities and are usually evenly distributed in the tissue. Limanda limanda, Tetraodon fluviatilis were the species with the highest lipid contents in the hepatocytes; Chromis, Amphiprion and Corydoras are particularly rich in glycogen. The hepatocytes of all species contain membrane-bound inclusion bodies which, according to their ultrastructure, are interpreted to represent peroxisomes. In most species intercellular bile canaliculi occur. The space of Disse is characterized by the absence of a basement lamina and the presence of a few filament-rich cells extending long cellular processes which are interconnected by desmosomes. Special lipid-containing cells were not been observed in the space of Disse.