title: 1 alpha, 25-Dihydroxyvitamin D3 directly induces fusion of alveolar macrophages by a mechanism involving RNA and protein synthesis, but not DNA synthesis.
abstract: The results of our present study indicate that 1 alpha, 25-dihydroxyvitamin D3[1 alpha, 25(OH)2D3] directly induces fusion of mouse alveolar macrophages without any participation of T-lymphocytes by a mechanism involving RNA and protein synthesis but not DNA synthesis. We have reported that 1 alpha, 25(OH)2D3 induces fusion of alveolar macrophages by a direct mechanism and by a spleen cell-mediated indirect mechanism [(1983) Proc. Natl. Acad. Sci. USA 80, 5583-5587]. Alveolar macrophages pretreated with or without anti-Thy 1.2 antibody and complement fused similarly when they were incubated with 1 alpha, 25(OH)2D3. The vitamin suppressed DNA synthesis, but it significantly enhanced RNA and protein synthesis. The 1 alpha, 25(OH)2D3-induced fusion was blocked by adding actinomycin D or cycloheximide, but not by hydroxyurea.
mesh_terms: D000818:Animals; D002117:Calcitriol / Q000494:pharmacology*; D002459:Cell Fusion / Q000187:drug effects; D003513:Cycloheximide / Q000494:pharmacology; D004261:DNA Replication / Q000187:drug effects*; D003609:Dactinomycin / Q000494:pharmacology; D006918:Hydroxyurea / Q000494:pharmacology; D007700:Kinetics; D008264:Macrophages / Q000187:drug effects / Q000276:immunology / Q000502:physiology*; D008297:Male; D051379:Mice; D008815:Mice, Inbred Strains; D014176:Protein Biosynthesis / Q000187:drug effects*; D014158:Transcription, Genetic / Q000187:drug effects*
chemical_list: D003609:Dactinomycin; D003513:Cycloheximide; D002117:Calcitriol; D006918:Hydroxyurea