Synthesis of 1,25-dihydroxyvitamin D3 by rat brain macrophages in vitro

✍ Scribed by I. Neveu; P. Naveilhan; C. Menaa; D. Wion; Dr. P. Brachet; M. Garabédian

• Publisher: John Wiley and Sons
• Year: 1994
• Tongue: English
• Weight: 696 KB
• Volume: 38
• Category: Article
• ISSN: 0360-4012
• DOI: 10.1002/jnr.490380212

✦ Synopsis

Cultured microglial cells were examined for their ability to metabolize 25-hydroxyvitamin D, (25-(OH) D,). Upon exposure to lipopolysaccharide, microglial cells produced a vitamin D metabolite which comigrated with synthetic 1,25-dihydroxyvitamin D, (1,25-(OH),D,) in two different systems of high performance liquid chromatography. This metabolite had the same affinity as synthetic 1,25-(OH),D, for the chick intestinal 1,25-(OH),D, receptor. Lipopolysaccharide-stimulated microglial cells incubated with 3 nM of 25-(OH) D, synthesized up to 5.76 fmol 1,25-(OH),D3/8 X lo5 cells/;?. hr. Microglial cells stimulated for 48 hr with interferon-? also produced a significant amount of 1,25-(OH),D, (4.17 fmol/8 X lo5 cells/2 hr). In contrast, levels of 1,25-(OH),D,

produced by resting microglial cells were barely detectable. It is concluded that activated brain macrophages may be committed to synthesize 1,25-(OH),D, in vitro. This raises the possibility that activation of microglial cells in vivo may be followed by an increase in the level of 1,25-(OH),D, in the central nervous system (CNS). These results support the emerging concept that the brain constitutes a target tissue for vitamin D metabolites.