Evidence for 1,25-dihydroxyvitamin D3 production by cultured porcine alveolar macrophages.
Previous studies have demonstrated that human alveolar and bone marrow macrophages when activated in vitro can metabolize 25-hydroxyvitamin[3H]D3 to 1 alpha,25-dihydroxyvitamin[3H]D3; however, to date no animal models to study this system have been available. In the present study, cultured porcine pulmonary alveolar macrophages from two animals were assayed for their capability for metabolism of 25-hydroxyvitamin[3H]D3. The porcine alveolar macrophages constitutively produced a metabolite of 25-hydroxyvitamin[3H]D3 which was identified as 1 alpha,25-dihydroxyvitamin[3H]D3 by high performance liquid chromatography. The apparent KM was in the range of 300 nM. Unlike human macrophages, treatment of porcine alveolar macrophages with lipopolysaccharide did not stimulate 1 alpha,25-dihydroxyvitamin[3H]D3 production. Addition of 1 alpha,25-dihydroxyvitamin-D3 to macrophages cultures led to a sensitive proportional inhibition of 1 alpha,25-dihydroxyvitamin[3H]D3 synthesis.
Reichel
H
H
Department of Biochemistry, University of California, Riverside 92521.
Bishop
J E
JE
Koeffler
H P
HP
Norman
A W
AW
D000818:Animals; D002117:Calcitriol / Q000096:biosynthesis*; D002851:Chromatography, High Pressure Liquid; D007700:Kinetics; D008070:Lipopolysaccharides / Q000494:pharmacology; D008264:Macrophages / Q000187:drug effects / Q000378:metabolism*; D011650:Pulmonary Alveoli / Q000166:cytology; D013552:Swine; D013556:Swine, Miniature / Q000378:metabolism*
D008070:Lipopolysaccharides; D002117:Calcitriol