title: Biosynthesis of the third (C3), eighth (C8), and ninth (C9) complement components by guinea pig hepatocyte primary cultures.
abstract: In the present report guinea pig hepatocyte primary cultures were established in order to study the synthesis of the eighth (C8) and ninth (C9) complement component. As reference-protein, the third complement component (C3) was measured antigenetically and hemolytically. Synthesis of C8 and C9 was determined by means of the hemolytic activity of the culture supernatant harvested every 24 h during a 6-day incubation period in vitro. The data to be reported demonstrated that the hepatocytes are able to synthesize spontaneously and secrete C8 and C9; in their culture medium a hemolytic activity of about 15-25 X 10(8) em/10(6) cells/24 h for C8 and of 25-90 x 10(8) em/10(6) cells/24 h for C9 were found. The same hepatocyte cultures produced 2500-6000 micrograms/10(6) cells/24 h of C3. Hemolytic C3 activity was also found in the culture media. The synthesis of C8 and C9 could be reversibly inhibited by addition of 30-50 micrograms cycloheximide per ml of culture medium. The kinetics of synthesis show a slight decrease after the first day of culture and a recovery in the following days up to a rate that is two- to threefold higher than that of the first day. The data suggest that hepatocytes could contribute to the production of C8 and C9 present in the plasma.
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D003176:Complement C3 / Q000096:biosynthesis*; D003185:Complement C8 / Q000096:biosynthesis*; D003186:Complement C9 / Q000096:biosynthesis*; D006168:Guinea Pigs; D006461:Hemolysis; D008099:Liver / Q000378:metabolism*
chemical_list: D003176:Complement C3; D003185:Complement C8; D003186:Complement C9