Morphological and functional development of plasma membranes of mouse hepatocytes: an autoradiographic study of asialoglycoprotein uptake during the postnatal period.
The morphological development of the postnatal mouse liver was studied with reference to the specialization of sinusoidal plasma membranes of hepatocytes. Numerous hemopoietic islands were distributed at random among hepatocytes at neonatal stages. The hemopoietic fronts of hepatocytes were flat and showed few structures indicating endocytotic and exocytotic activities. They gradually acquired structural characteristics of the sinusoidal region as the processes of the endothelial cells extended in the space between hemopoietic cells and hepatocytes. The degree of attenuation and fenestration of the sinusoidal endothelial cells increased as the postnatal day advanced. In the course of these changes, microvilli, pinocytotic pits, and vesicles of sinusoidal regions of hepatocytes increased as well. The functional development of sinusoidal regions of hepatocytes was investigated by the quantitative analysis of autoradiograms of [3H]asialoorosomucoid (ASOR). Silver grains were distributed only in the regions where the structural specializations of the sinusoidal region were observed. They increased as the maturation of sinusoidal structure advanced. These results suggest that the sinusoidal regions of hepatocytes specialize structurally and functionally, as regards ASOR-uptake capability, in correlation with the structural establishment of sinusoids.
D000818:Animals; D001212:Asialoglycoproteins / Q000378:metabolism*; D001345:Autoradiography; D002462:Cell Membrane / Q000378:metabolism / Q000502:physiology*; D008099:Liver / Q000166:cytology* / Q000378:metabolism; D051379:Mice; D008809:Mice, Inbred C3H; D008854:Microscopy, Electron; D009024:Morphogenesis; D009961:Orosomucoid / Q000031:analogs & derivatives / Q000378:metabolism; D013997:Time Factors
D001212:Asialoglycoproteins; D009961:Orosomucoid; C017030:asialoorosomucoid