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Morphometric analysis of liver in rainbow trout: Quantitatively defining an organ of xenobiotic metabolism
Marine Environmental Research 17 (1985) 238-239
Morphometric Analysis of Liver in Rainbow Trout: Quantitatively Defining an Organ of Xenobiotic Metabolism David E. Hinton, James A. Hampton & R. Clark Lantz Department of Anatomy, School of Medicine, West Virginia University, Morgantown, West Virginia 26506, USA
The process of uptake, metabolism and eventual biliary excretion of xenobiotics by the teleost liver affords an opportunity for alteration within at least the following cells: sinusoidal endothelial, perisinoidal fat-storing (vitamin A-containing),t hepatocytes and biliary epithelial (of preductules, ductules and intrahepatic ducts). Our understanding ojthe existence and role(s) in physiologic and pathobiologic phenomena of non-hepatocytic populations of cells in teleost liver has been hampered by the use of immersion fixation procedures obviating resolution and analysis of sinusoidal lining cells and by the subjective nature of light and electron micrographs. The purpose of this study was to quantitatively define the rainbow trout (Salmo gairdneri, Richardson) liver. Computer-assisted morphometry 2 was conducted on livers of actively spawning 5 year old male and female trout ( Wytheville strain).
Fixative delivery was by portal venous perfusion under physiological rates of flow. 3 Hepatocytes of female trout were more numerous and smaller than those of males (Table 1). Biliary epithelial cells occupied 1-9 ~o of total liver volume. Of the biliary epithelial volume compartment, 77 ~ was occupied by bile preductular cells. The ratio of Nv hepatocytes to Nv bile preductular cells (7-8 to 1) supports the tubular concept 4'5 of teleost liver cell architecture (Table 1). When extended to hepatocyte cytoplasmic components, surface density (Sv) of granular and smooth endoplasmic reticulum were estimated (Table 1). Since these membranes 238 Marine Environ. Res. 0141-1 I36/85/$03-30 ( Elsevier Applied Science Publishers Ltd,
England, 1985. Printed in Great Britain
Morphometric analysL~ of liver in rainbow trout
239
TABLE 1
Morphometric Data in Rainbow Trout Liver Parameter I:,.~
l?b N, c S,.a
Parenchyma Vascular Hepatocytes Biliary Hepatocytes* Hepatocytes* Bile preductular ceils GER SER
Value 85.5 :~ 14.5 "o 82.1 "o 1.92 '.'0 990_ 329 (female) 1 613 + 280 (male) 9-08 + 2.96 (female) 5.40 +_ 1.11 (male) 1.07 ___0.61 (female) 0.77 + 0.37 (,male) 5498 _+ 1 523 719 +_ 523
a vv = Percent of total liver volume occupied by each parameter. b 17= Average hepatocyte volume (/.am3). N,. = Numerical density--number of cells ( × | 0 S ) / c m 3 liver. d Sv = Surface density--surface area/unit volume (mm-'/mm3). b-d Values listed are means + I SD (N = 13 females and N = 8 males). GER Granular endoplasmic reticulum. SER Smooth endoplasmic reticulum. * P < 0-01 by analysis of variance females vs. males. are the loci for the m i c r o s o m a l m i x e d f u n c t i o n o x y g e n a s e e n z y m e s , baseline values are r e p o r t e d . W h e n e x p r e s s e d per unit v o l u m e o f h e p a t o c y t e c y t o p l a s m , n o sex differences were seen in these a n d o t h e r organelles. Results show sex differences in h e p a t o c y t e s are restricted to number and average volume. Based on their i m p o r t a n c e in m a m m a l i a n liver toxicity a n d their p o s i t i o n between h e p a t o c y t e s a n d the m i c r o v a s c u l a t u r e a n d between h e p a t o c y t e s a n d the biliary s y s t e m , n o n h e p a t o c y t i c cells o f teleost liver w a r r a n t c o n s i d e r a t i o n in studies d i r e c t e d t o w a r d m e c h a n i s m s o f toxicity. S u p p o r t e d by G r a n t N o . P C M - 8 3 1 6 0 0 2 f r o m the US N a t i o n a l Science Foundation. REFERENCES 1. Wake, K. Int. Rev. Cytol., 66, 303-53 (1980). 2. Weibel, E. R. In Stereological Methods, Vol. 1, Academic Press, London, 1979. 3. Schmidt, D. & Weber, L. J. Fish. Res. Bd Can., 30, 1301 -8 (1973). 4. Shore, T. & Jones, H. J. Physiol. Lond., 10, 408-28 (1889). 5. Tanuma, Y., Ohata, M. & Ito, T. Arch. Histol. Jap., 45, 453-72 (1982).
Morphometric Analysis of Liver in Rainbow Trout: Quantitatively Defining an Organ of Xenobiotic Metabolism David E. Hinton, James A. Hampton & R. Clark Lantz Department of Anatomy, School of Medicine, West Virginia University, Morgantown, West Virginia 26506, USA
The process of uptake, metabolism and eventual biliary excretion of xenobiotics by the teleost liver affords an opportunity for alteration within at least the following cells: sinusoidal endothelial, perisinoidal fat-storing (vitamin A-containing),t hepatocytes and biliary epithelial (of preductules, ductules and intrahepatic ducts). Our understanding ojthe existence and role(s) in physiologic and pathobiologic phenomena of non-hepatocytic populations of cells in teleost liver has been hampered by the use of immersion fixation procedures obviating resolution and analysis of sinusoidal lining cells and by the subjective nature of light and electron micrographs. The purpose of this study was to quantitatively define the rainbow trout (Salmo gairdneri, Richardson) liver. Computer-assisted morphometry 2 was conducted on livers of actively spawning 5 year old male and female trout ( Wytheville strain).
Fixative delivery was by portal venous perfusion under physiological rates of flow. 3 Hepatocytes of female trout were more numerous and smaller than those of males (Table 1). Biliary epithelial cells occupied 1-9 ~o of total liver volume. Of the biliary epithelial volume compartment, 77 ~ was occupied by bile preductular cells. The ratio of Nv hepatocytes to Nv bile preductular cells (7-8 to 1) supports the tubular concept 4'5 of teleost liver cell architecture (Table 1). When extended to hepatocyte cytoplasmic components, surface density (Sv) of granular and smooth endoplasmic reticulum were estimated (Table 1). Since these membranes 238 Marine Environ. Res. 0141-1 I36/85/$03-30 ( Elsevier Applied Science Publishers Ltd,
England, 1985. Printed in Great Britain
Morphometric analysL~ of liver in rainbow trout
239
TABLE 1
Morphometric Data in Rainbow Trout Liver Parameter I:,.~
l?b N, c S,.a
Parenchyma Vascular Hepatocytes Biliary Hepatocytes* Hepatocytes* Bile preductular ceils GER SER
Value 85.5 :~ 14.5 "o 82.1 "o 1.92 '.'0 990_ 329 (female) 1 613 + 280 (male) 9-08 + 2.96 (female) 5.40 +_ 1.11 (male) 1.07 ___0.61 (female) 0.77 + 0.37 (,male) 5498 _+ 1 523 719 +_ 523
a vv = Percent of total liver volume occupied by each parameter. b 17= Average hepatocyte volume (/.am3). N,. = Numerical density--number of cells ( × | 0 S ) / c m 3 liver. d Sv = Surface density--surface area/unit volume (mm-'/mm3). b-d Values listed are means + I SD (N = 13 females and N = 8 males). GER Granular endoplasmic reticulum. SER Smooth endoplasmic reticulum. * P < 0-01 by analysis of variance females vs. males. are the loci for the m i c r o s o m a l m i x e d f u n c t i o n o x y g e n a s e e n z y m e s , baseline values are r e p o r t e d . W h e n e x p r e s s e d per unit v o l u m e o f h e p a t o c y t e c y t o p l a s m , n o sex differences were seen in these a n d o t h e r organelles. Results show sex differences in h e p a t o c y t e s are restricted to number and average volume. Based on their i m p o r t a n c e in m a m m a l i a n liver toxicity a n d their p o s i t i o n between h e p a t o c y t e s a n d the m i c r o v a s c u l a t u r e a n d between h e p a t o c y t e s a n d the biliary s y s t e m , n o n h e p a t o c y t i c cells o f teleost liver w a r r a n t c o n s i d e r a t i o n in studies d i r e c t e d t o w a r d m e c h a n i s m s o f toxicity. S u p p o r t e d by G r a n t N o . P C M - 8 3 1 6 0 0 2 f r o m the US N a t i o n a l Science Foundation. REFERENCES 1. Wake, K. Int. Rev. Cytol., 66, 303-53 (1980). 2. Weibel, E. R. In Stereological Methods, Vol. 1, Academic Press, London, 1979. 3. Schmidt, D. & Weber, L. J. Fish. Res. Bd Can., 30, 1301 -8 (1973). 4. Shore, T. & Jones, H. J. Physiol. Lond., 10, 408-28 (1889). 5. Tanuma, Y., Ohata, M. & Ito, T. Arch. Histol. Jap., 45, 453-72 (1982).