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Query: UMLS:C0338671 (Steroids)
 9,479 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In order to obtain specific antisera for use in the enzyme immunoassay of 25-hydroxyvitamin D3, three hapten-carrier conjugates having different lengths of bridges at the C-3 position were prepared from 25-hydroxyvitamin D3 by coupling with bovine serum albumin using the active ester method. The specificity of anti-25-hydroxyvitamin D3 antisera elicited in rabbits was tested by a cross-reaction study with closely related secosterols and by measuring the plasma levels of 25-hydroxyvitamin D3 by means of radioimmunoassay using tritium-labeled antigen. The results indicated that the specificity of the antisera obtained is higher than that of vitamin D-binding protein, and that some of these antisera are suitable for enzyme immunoassay.
Steroids 1992 Oct
PMID:Production and specificity of antisera raised against 25-hydroxyvitamin D3-[C-3]-bovine serum albumin conjugates. 145 56

A synthesis and an in vitro evaluation of side chain-unsaturated analogs 3 and 4 of 24a, 24b-dihomo-1,25-dihydroxycholecalciferol (1) are described, Novel C23a, 24-vitamin D synthons (sulfone 10 and aldehyde 11) were used for the synthesis of analog 4 and for the efficient preparation of the parent compound 1. The synthetic approach developed allows the use of easily available side chain fragments, such as oxirane 12 or Wittig reagent 15 for the preparation of compound 1 and analog 4, respectively. Introduction of a 24aE double bond results in a selective, 1000-fold increase in the binding affinity of analog 4 for the vitamin D receptor, compared to the affinity of 1, whereas the affinity of 4 for the vitamin D-binding protein and the activity in stimulating the differentiation of human promyelocytic leukemia HL-60 cells remained largely unchanged.
Steroids 1997 Jul
PMID:Synthesis and in vitro evaluation of side chain-unsaturated analogs of 24a,24b-dihomo-1,25-dihydroxycholecalciferol. 925 95

Synthesis of novel C19-modified affinity and photoaffinity analogs of vitamin D3 and 25-hydroxyvitamin D3(25-OH-D3) is described. A key step in the synthesis is a Horner-Emmons reaction between C19-nor-cyclovitamin D3-C19-ketone or C19-nor-25-hydroxy-cyclovitamin D3-C19-ketone and diethyl cyanomethylphosphonate. Competitive radioligand binding assays with human serum vitamin D-binding protein (DBP) and 5E-[19-(2-bromoacetoxy)methyl]25-hydroxyvitamin D3 and 5E-25-hydroxyvitamin D3-19-methyl[(4-azido-2-nitro)phenyl]-glycinate, 25-OH-D3-analogs containing affinity and photoaffinity probes at C19-position, demonstrated that these compounds displaced radiolabeled 25-OH-D3 from the binding pocket of DBP in a dose-dependent manner. Thus, these affinity and photoaffinity analogs are potentially useful in determining the ligand binding site topographies of DBP and possibly the vitamin D receptor.
Steroids 1998 Apr
PMID:Synthesis and binding-analysis of 5E-[19-(2-bromoacetoxy)methyl]25-hydroxyvitamin D3 and 5E-25-hydroxyvitamin D3-19-methyl[(4-azido-2-nitro)phenyl]glycinate: novel C19-modified affinity and photoaffinity analogs of 25-hydroxyvitamin D3. 958 57

In this article, we describe the development of a general synthetic strategy to functionalize the C-6 position of vitamin D3 and its biologically important metabolites, i.e. 25-hydroxyvitamin D3 (25-OH-D3) and 1alpha,25-dihydroxyvitamin D3 [1,25(OH)2D3]. We employed Mazur's cyclovitamin D method to synthesize vitamin D3 analogs with several functionalities at the C-6 position. In addition, we synthesized 6-(3-hydroxypropyl) and 6-[(2-bromoacetoxy)propyl] derivatives of 25-OH-D3 15 and 16, respectively, and 6-(3-hydroxypropyl) derivative of 1,25(OH)2D3 17. Competitive binding assays of 15-17 with human serum vitamin D-binding protein showed that all these analogs specifically bound to this protein, although with significantly lower affinity than the 25-OH-D3, the strongest natural binder, but with comparable affinity with 1,25(OH)2D3, the hormone. On the other hand, 6-[3-hydroxypropyl], 1alpha,25-dihydroxyvitamin D3 17 did not show any specific binding for recombinant nuclear vitamin D receptor. These results indicated that the region containing the C-6 position of the parent seco-steroid [1,25(OH)2D3] may be an important recognition marker towards vitamin D receptor binding. Information, delineated in this article, will be important for evaluating structure-activity relationship in synthetic analogs of vitamin D and its metabolites.
Steroids 1999 Apr
PMID:C-6 functionalized analogs of 25-hydroxyvitamin D3 and 1alpha,25-dihydroxyvitamin D3: synthesis and binding analysis with vitamin D-binding protein and vitamin D receptor. 1039 84