Synthesis of 1,25-dihydroxyvitamin D3 by spleen cells isolated from two patients with myelofibrosis and a normal subject.
The ability to synthesise [3H]1,25(OH)2D3 was studied in spleen cells incubated in short-term primary culture with [3H]25(OH)D3 which were isolated from two patients with idiopathic myelofibrosis and from one normal subject. Formation of a metabolite co-chromatographing with authentic 1,25(OH)2D3 on three different high-performance liquid chromatography systems was observed for cells from all three patients. [3H]1,25(OH)2D3 synthesis was 0.37 and 1.6 fmol/10(6) cells/incubation for cells with a density below that of lymphocyte separating media (1.077 g/ml) for the two myelofibrotic patients respectively and 0.15 fmol/10(6) cells/incubation for the normal subject. The most likely cell type capable of this synthesis were those of the monocyte-macrophage lineage which would have been present in abnormally high numbers in the patients with myelofibrosis. However, the exact identity of the cell-type responsible could not be determined because of the heterogeneity of cell types present. The observation that spleen cells from two patients with myelofibrosis and from a normal accident victim could metabolise [3H]25(OH)D3 to its active form [3H]1,25(OH)2D3 suggests a possible role for this metabolite in spleen haematopoiesis.
Hayes
M E
ME
Department of Medicine, Manchester University, England.
Davies
M
M
Bayley
D
D
Lin Yin
J A
JA
Mawer
E B
EB
D002117:Calcitriol / Q000032:analysis / Q000096:biosynthesis*; D002851:Chromatography, High Pressure Liquid; D006801:Humans; D066298:In Vitro Techniques; D055728:Primary Myelofibrosis / Q000378:metabolism*; D012016:Reference Values; D012588:Scintillation Counting; D013056:Spectrophotometry, Ultraviolet; D013154:Spleen / Q000166:cytology / Q000378:metabolism*
D002117:Calcitriol