24,R-25-dIhydroxyvitamine

DHD = 24(R),25-dihydroxyvitamin D 250H = 25-hydroxyvitamin D PTH = parathyroid hormone CT = calcitonin Pj = inorganic phosphorus. 

C3oH44BrN03, Desoxycholic acid p-bromoanilide, 38B, 554 C30H44O7, 6a,7a 17,24 22,26-Triepoxy-5,25,26-trihydroxy-5a,17a-ergost-2-en-l-one ethyl ether, 42B, 411 C30H49O4, 24(R),25-Dihydroxyvitamin d2r 45B, 578 C31H44O2S2 r 3/3-Acetoxy-6,7-epidithio-19-norlanosta-5,7,9,11-tetra-ene, 42B, 412... 

Reddy GS, Tsemg KY, Thomas BR, Dayal R, Norman AW (1987) Isolation and identification of l,23-dihydroxy-24,25,26,27-tetranorvitamin D3, a new metabolite of 1,25-dihydroxyvitamin D3 produced in rat kidney. Biochemistry 26 324-331... 

Zhu J, Barycki R, Chiellini G, DeLuca HF (2010) Screening of selective inhibitors of la,25-dihydroxyvitamin D3 24-hydroxylase using recombinant human enzyme expressed in Escherichia coli. Biochemistry 49 10403-10411... 

Iwasaki H, Hosotani R, Kasama T, Takayama H, 2483. Yamada S, SudaT (1997) la,25-Dihydroxyvitamin D3-24-hydroxylase (CYP24) hydroxylates the carbon at the end of the side chain (C-26) of the C-24-fluorinated analog of la,25-dihydroxyvitamin... 

Some conflicting statements have been made concerning the relative potencies of compounds possessing of the 24 R)- and 24(iS)-configuration in the vitamin D3 side chains. DeLuca (185) claims that both synthetically derived 24-hydroxyvitamin D3 isomers stimulate intestinal calcium transport almost equally well in the rat and has shown that the 24(S)-isomer has little or no activity in bone calcium resorption or in bone formation, whereas the 24(/ )-isomer is almost as active as 25-hydroxyvitamin D3 in these in vivo tests. However, Atkins (7) claims that both diastereo-isomers of 24,25-dihydroxyvitamin D3 are potent stimulators of bone resorption in tissue culture and there is no significant difference between the (R)- and (5)-forms. Boris (24) recently also showed that both 24 R)-and 24(/S)-isomers of la,24,25-trihydroxyvitamin D3 promote bone mineralization almost equally well in cockerels. Whether the differentiation of the 24(i )- and 24(5)-diastereoisomers in bone formation and resorption occurs only in the absence of the la- and the 25-hydroxy substituents is not known at this time, but it seems unlikely. 

Amir H, Karas M, Giat J, Danilenko M, Levy R, Yermiahu T, Levy J, Sharoni Y (1999) Lycopene and 1,25-dihydroxyvitamin D3 cooperate in the inhibition of cell cycle progression and induction of differentiation in HL-60 leukemic cells. Nutr Cancer 33 105-112... 

Noda, M., Vogel, R.L., Craig, A.M., Prahl, J., DeLuca, H.F. and Denhardt, D.T. 1990. Identification of a DNA sequence responsible for binding of the l-alpha,25-dihydroxyvitamin D3 receptor and 1,25-dihydroxyvitamin D3 enhancement of mouse secreted phosphoprotein 1 (SPP-1 or osteopontin) gene expression. Proc. Natl. Acad. Sci. USA 87(24) 9995-9. 

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