Functional units in rainbow trout (Salmo gairdneri) liver: I. Arrangement and histochemical properties of hepatocytes

Abstract

The architectural arrangement and selected histochemical properties of hepatocytes in the rainbow trout (Salmo gairdneri Richardson) were examined. Light and transmission electron microscopic (TEM) examination following fixation by portal venous perfusion revealed a tubular arrangement of hepatocytes. Lobules, as defined in the adult mammal, were absent. Biliary epithelial cells associated with bile preductules and ductules were a prominent feature of trout liver. Patterns and location of reaction products for glucose-6-phosphatase (G-6-Pase), glucose-6-phosphate dehydrogenase (G-6-PDH), and magnesium-dependent adenosine triphosphatase (ATPase), enzymes preferentially distributed in mammalian liver, were demonstrated in trout liver. A slightly heavier staining pattern for G-6-Pase was seen around presumptive portal venules but all other enzyme reaction patterns were uniform throughout the liver parenchyma. Following ATPase localization, four sizes of biliary passageways (canaliculi, bile preductules, ductules, and ducts) were visualized. Maximum glycogen retention was achieved with freeze-drying and glycolmethacrylate embedding and with this method intense, uniform glycogen staining was observed in all areas of the liver. Companion TEM examinations revealed large depots of glycogen within hepatocytes. The results are important for interpretation and description of the effects of toxic/carcinogenic alteration on trout liver.

The Ultrastructure and Histology of Hepatocellular Carcinomas of English Sole (Parophrys vetulus) from Puget Sound, Washington

“…1) has been previously described by other investigators to be organized into dual-plated muralia (44,46). This architecture is similar in appearance to what is currently and more accurately described as a hepatic tubular organization (17,18,35,60). Bile ducts and vascular components were each scattered independently throughout the liver rather than organized into portal triads as they are in mammals.…”

Morphology and Histochemistry of the Liver of Carnivorous Fish Hemisorubim platyrhynchos

“…In the liver parenchyma of H. platyrhynchos, the hepatocytes are arranged in cords and it was no division in lobules and portal triads was observed, as evidenced in other teleosts (Kendall & Hawkins;Hampton et al, 1985;Gonzalez et al, 1993;Vicentini et al, 2005;Bombonato et al;Bertolucci et al). The hepatocytes of H. platyrhynchos are polygonal and present basal nucleus and apical cytoplasm with few glycogen granules but large amount of lipids, similar to observed in Sparus aurata (El-Bakary & El-Gammal, 2010).…”

Structure of and energy reserves in the liver of wild and cultured yellowtail flounder, Limanda ferruginea

“…In sexually mature flatfish species, such as European flounder (Platichthys flesus), winter flounder (Pseudopleuronectes americanus), and plaice (Pleuronectes platessa), the pancreatic tissue is more scattered throughout the liver (Timashova 1982;Ko¨hler 1990;Murchelano and Wolke 1991;March and Reisman 1995;Vethaak and Wester 1996). As in other fish, the histomorphology of the liver in sexually immature L. ferruginea causes difficulties in determining the functional liver units and in explaining the appearance of histopathological changes (Hampton et al 1985(Hampton et al , 1988Morrison 1987;Stehr et al 1988;Ko¨hler 1989;Krause and Cutts 1994;Vethaak and Wester 1996). In vivo microscopy of liver microvasculature in rainbow trout revealed a repeating pattern of alternation between afferent and efferent regions (Hinton and Lauren 1989).…”

“…These differences in lipid content between cultured and wild fish, and between cultured females and males were b statistically significant, while there were no significant differences among the groups or sexes for glycogen content. Hatchery-reared rainbow trout (Salmo gairdneri) and channel catfish (Ictalurus punctatus) showed an abundance of glycogen within the hepatocytes (Hinton and Pool 1976;Hampton et al 1985), likely caused by diet. Exposure to chemical contaminants may cause depletion of hepatocellular glycogen, as has been suggested in several species such as winter flounder (P. americanus) and male bullheads (Cottus gobio L.) (Carr et al 1991;Bucher et al 1992).…”

“…The histomorphology of liver of flatfish such as winter flounder (Pseudopleuronectes americanus), European flounder (Platichthys flesus), English sole (Pleuronectes vetulus), and dab (Limanda limanda) resembles that of other teleosts (Hampton et al 1985(Hampton et al , 1988Morrison 1987;Stehr et al 1988;Ko¨hler 1989;Vethaak and Wester 1996, and references therein). The basic morphology and physiology of the liver of yellowtail flounder have not been studied to date, and sex differences in the studied species, and the potential differences between wild and cultured fish have also received little attention.…”