Metabolism of the cell differentiating agent 1alpha,25(OH)2-16-ene-23-yne vitamin D3 by leukemic cells.
The metabolism of 1alpha,25(OH)2D3 and 1alpha,25(OH)2-l6-ene-23-yne-D3 is examined by in vitro incubation of the steroid hormones with WEHI-3 myeloid leukemia cells. Two experimental systems were used to evaluate the metabolism of each compound: (a) a double label incubation was performed to determine both the propensity for metabolism of each analog and the in vitro half-life of the analogs; and (b) separate single label incubations were performed to determine the metabolite profile derived from each of the analogs. The double label WEHI-3 cell incubation with 25 nM [23,24(3)H]1alpha,25(OH)2D3 and 25 nM [25(14)C]1alpha,25(OH)2-16-ene-23-yne-D3 produced a single comigrating metabolite of higher polarity from each of the parent compounds in a gradient HPLC chromatogram. The half-life of each analog determined from this in vitro incubation was 6.9 and 6.7 h for 1alpha,25(OH)2D3 and 1alpha,25(OH)2-16-ene-23-yne-D3, respectively. Individual incubations of 1alpha,25(OH)2D3 yielded a metabolite that comigrates with 1alpha,24,25(OH)2D3 standard in each of three independent HPLC separations. Individual incubations with [25(14)C]1alpha,25(OH)2-16-ene-23-yne-D3 generated multiple metabolites, which are resistant to degradation as evaluated by intermediate build-up, are of increasing polarity and do not comigrate with the 1alpha,24,25(OH)3D3 standard. From these studies it is determined that 1alpha,25(OH)2-l6-ene-23-yne-D3 is metabolized differently but not preferentially compared to 1,25(OH)2D3 in myelogenous leukemia cells.
Satchell
D P
DP
Department of Biochemistry, University of California-Riverside, 92521, USA.
Norman
A W
AW
D000818:Animals; D000970:Antineoplastic Agents / Q000378:metabolism / Q000494:pharmacology; D002117:Calcitriol / Q000031:analogs & derivatives* / Q000378:metabolism / Q000494:pharmacology; D002454:Cell Differentiation / Q000187:drug effects*; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D007951:Leukemia, Myeloid / Q000188:drug therapy / Q000378:metabolism* / Q000473:pathology; D051379:Mice; D014407:Tumor Cells, Cultured
D000970:Antineoplastic Agents; D002117:Calcitriol; C064183:Ro 23-7553