Electron microscopy and morphometry of canalicular differentiation in fetal and neonatal rat liver

In order to complement previous electron microscopic studies on the differentiation of the biliary pole of the rat hepatocyte during perinatal maturation, a morphometric analysis was undertaken of the bile canaliculi in fetal and adult rat liver. Four morphologic canalicular types were found and morphometrically characterized using a surface/volume relation (s/v index) as key parameter. The surface/volume relation of the canaliculus in fetal and postnatal maturation as well as in the adult rat liver supports the previously formulated hypothesis that these different types correspond to successive maturation stages of the biliary pole of the hepaocyte. Furthermore, the s/v index of type 3 canaliculus supports the concept that this canalicular type represents a canalicular structure inefficient for secretion.