Heinrich K. Schnoes

Novel synthesis of 19-nor vitamin d compounds

A convergent synthesis of 19-nor-vitamin D compounds, specifically 19-nor-1α,25-dihydroxyvitamin D₃, is disclosed. The synthesis can also readily be utilized for preparing other 1α-hydroxylated 19-nor-vitamin D compounds. The key step in the synthesis is a suitable application of Lythgoes procedure i.e. a Horner-Wittig reaction of the lithium anion of a phosphine oxide with a Windaus Grundmann ketone to give, after any necessary deprotection, the desired 19-nor-vitamin D compound.

Biological activity of 1,25-dihydroxyvitamin D2 in the chick

1,25-Dihydroxyvitamin D2 has been prepared from 25-hydroxyvitamin D2 using rachitic chick kidney mitochondria. This metabolite was highly purified by Sephadex LH-20 chromatography and by preparative high-pressure liquid chromatography. Its purity was assessed by analytical high-pressure liquid chromatography which revealed no other 254-nm absorbing material and by mass spectrometry. The concentration of dilute solutions of 1,25-dihydroxyvitamin D2 was determined by high-pressure liquid chromatography and deflection of the 254-nm column monitor. The 1,25-dihydroxyvitamin D2 was then shown to be 1/5 to 1/10 as active as 1,25-dihydroxyvitamin D3 in the chick while it had previously been shown to be equal in activity in the rat. Thus, discrimination against the vitamin D2 side chain by the chick persists in the metabolically active 1,25-dihydroxyvitamin D compounds.

23,25-Dihydroxyvitamin D3

Fibroblast growth factor-23 (FGF23) is a circulating hormone that acts to correct hyperphosphatemic states by inhibiting renal phosphate reabsorption and to prevent hypervitaminosis D by feedback repressing 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) biosynthesis. FGF23 gene expression in the osteoblast/osteocyte is induced by the nuclear vitamin D receptor (VDR) bound to 1,25(OH)2D3, but cycloheximide sensitivity of this induction suggests that it may occur largely via secondary mechanisms requiring cooperating transcription factors. We therefore sought to identify 1,25(OH)2D3-regulated transcription factors that might impact FGF23 expression. Although neither leptin nor interleukin-6 (IL-6) alone affects FGF23 expression, leptin treatment was found to potentiate 1,25(OH)2D3 upregulation of FGF23 in UMR-106 cells, whereas IL-6 treatment blunted this upregulation. Genomic analyses revealed conserved binding sites for STATs (signal transduction mediators of leptin and IL-6 action) along with transcription factor ETS1 in human and other mammalian FGF23 genes. Further, STAT3, STAT1, ETS1, and VDR mRNAs were induced in a dose-dependent manner by 1,25(OH)2D3 in UMR-106 cells. Bioinformatic analysis identified nine potential VDREs in a genomic interval containing human FGF23. Six of the putative VDREs were capable of mediating direct transcriptional activation of a heterologous reporter gene when bound by a 1,25(OH)2D3-liganded VDR complex. A model is proposed wherein 1,25(OH)2D3 upregulates FGF23 production directly via multiple VDREs and indirectly via induction of STAT3, ETS1, and VDR transcription factors that are then activated via cell surface and intracellular signaling to cooperate in the induction of FGF23 through DNA looping and generation of euchromatin architecture.

Method of preventing milk fever in dairy cattle

A method for prophylactically treating dairy cattle for parturient paresis by administering to cattle vitamin D derivatives which are characterized by the presence of a hydroxyl group at at least one of the C-1 and C-25 positions and a metabolically stable blocking group at the C-24 position in an amount sufficient to induce said prophylaxsis.

A convenient synthesis of (24S)-1α-hydroxyvitamin D2

A new method was developed for the synthesis of (2R)- and (2S)-2,3-dimethylbutyl p-tolyl sulphone from a chiral sulphinate ester, and applied to the synthesis of (24S)-1α-hydroxyvitamin D2; this new 24-epimer of vitamin D2 has a distinct biological activity profile, differing qualitatively from that known for the (24S)-isomer.