Morphological Aspects of Plasma Protein Synthesis and Secretion by the Hepatic Cells

Functional Hepatocellular Heterogeneity for the Production of Plasma Proteins

“…With the remarkable exception of im munoglobulins synthesized by plasma cells, at least 30 different plasma proteins are pro duced by the liver, as established by numer ous works published between 1950 and 1983 (see references in [1]). In man, these proteins represent about 55 g/1 of plasma and their structures as well as their functions are very heterogeneous.…”

“…The group of sinusoidal cells, com posed of Kupffer, Ito and endothelial cells, is able to produce small amounts of plasma proteins, usually in conjunction with hépa tocytes. Thus a,-antitrypsin, a protein made largely by hépatocytes [1,4], is also synthe sized by Kupffer cells [10]. Retinol bindingprotein is produced by both Ito cells and hepatocytes [11], while von Willebrand fac tor comes from endothelial cells only [12].…”

“…Only the two first cells are engaged in plasma protein synthesis. Hepatocytes, which form about 78% of the hepatic cellular volume [9], synthesize al most all the proteins produced by the liver and its is now well established that these cells are not specialized in the production of a given plasma protein [ 1 ]. However, this situ ation does not exclude, as will be discussed below, that hepatocytes may be functionally synthesis needs to be more completely inves tigated.…”

Use of Placental Cord Serum in Cultures of Human Fetal Hepatocytes: Its Assessment with Carbamyl Phosphate Synthetase and Argininosuccinate Lyase as Marker Enzymes.

“…The most extensively studied property of cultured fetal hepatocytes has been their ability to synthesize and secrete plasma proteins. Biochemical and immunological studies have clearly demonstrated that their synthesis is a specialized function of hepatocytes [16]. Albumin secretion could be detected in primary cultures of fetal liver cells even after 11 days of culture [17].…”

In situ Hybridization: Application to the Study of Gene Expression during Experimental Hepatocarcinogenesis and Human Hepatocellular Carcinoma

“…In immunohistochemistry, the notorious problems of speci ficity are due to the very nature of the anti gen-antibody interaction which depends on the recognition of target epitopes which may be as short as 10 amino acids and, therefore, shared by unrelated proteins in the cell. Moreover, distortion or masking of anti genic determinants by heating during paraf fin embedding or inadequate fixation may lead to false-negative results [4], In addition, endogenous proteins actually synthesized by the cells cannot be distinguished from exoge nous proteins that have entered the cells in vivo or during the fixation or permeabilization procedures. The in situ hybridization (ISH) technique represents a new tool of invaluable interest for analyzing gene ex pression at the cellular level.…”