Abstract
Two new metabolites of vitamin D2 were produced by perfusing kidneys, isolated from D-sufficient normocalcemic rats with pharmacological concentration (2×10−6M) of 25-hydroxyvitamin D2 [ 25(OH)D2 ]. They were isolated and purified from the lipid extract of the perfusate using high performance liquid chromotography. By means of ultraviolet absorption spectrophotometry, mass spectrometry and specific chemical reactions, the new metabolites were identified as 24, 25, 28-trihydroxyvitamin D2 [ 24, 25, 28(OH), D2 ] and 24, 25, 26-trihydroxyvitamin D2 [ 24, 25, 26 (OH)3D2]. Along with the two new metabolites 24, 25-dihydroxyvitamin D2 [ 24, 25(OH)2D2 ] was isolated and it was also demonstrated that the two new metabolites were formed from 24, 25(OH)2D2. Thus, our results indicate that 25(OH)D2 is first hydroxylated at C-24 to form 24, 25(OH)2D2 which is then further hydroxylated at C-28 and C-26 to form 24, 25, 28(OH)3D2 and 24, 25, 26(OH)3D2 respectively. In order to demonstrate the formation of the new metabolites under physiological conditions, 3H-25(OH)D2 was biologically produced by perfusing livers isolated from D-deficient rats with 3H-vitamin D2 (15Ci/mmol). Using 3H-25(OH)D2, we demonstrated the formation of the new metabolites when a concentration of 25(OH)D2 as low as (8×10−10M) was used as the substrate. Thus our study describes for the first time, a novel metabolic pathway for 25(OH) D2 in a mammalian kidney under physiological conditions.
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Reddy, S., Tserng, KY., Ray, R. et al. A NOVEL METABOLIC PATHWAY FOR 25–HYDROXYVITAMIN D2 IN A MAMMALIAN KIDNEY. Pediatr Res 21 (Suppl 4), 345 (1987). https://doi.org/10.1203/00006450-198704010-01067
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DOI: https://doi.org/10.1203/00006450-198704010-01067