Steroid phosphates

Catalytic turnover has also been seen in radical relay chlorinations in which the template is temporarily linked to the substrate in a mixed metal complex. The steroid phosphate (22) and catalytic ligand... 

Catalytic turnover has also been seen in radical relay chlorinations in which the template is temporarily linked to the substrate in a mixed metal complex. The steroid phosphate (22) and catalytic ligand (23) both bind to zinc in a mixed complex, and the iodine atom of (23) directs chlorination of (22) at C-9 with reasonable selectivity (Scheme 25). Five or more turnovers are seen, when only 10% of the catalyst (23) is used. ... 

Steroid-indnced calcinm deposits in the cornea have been reported. Patients with such persistent epithelial defects snch as postoperative inflammation, penetrating keratoplasty, and a history of herpetic keratitis and dry eye have developed a calcific band keratopathy after topical nse of a steroid phosphate formnlation. 

A novel and versatile synthesis of dialkyl steroid phosphates employs the steroidal alkoxyl radical (545), generated by photolysis of the corresponding nitrite. In the presence of a trialkyl phosphite, the radical attacks at phosphorus to give a phosphoranyl radical (546), which loses one of its four alkyl groups to give the desired phosphate (547). The preference for expulsion of one of the small alkyl groups, rather than the steroidal moiety, is thought to be determined by... 

Enzyme-catalysed desulfuration of steroids plays an important role in steroid biosynthesis and may provide a source of steroids in the growth and proliferation of breast cancer. Inhibition studies of estrone sulfatase with both steroidal and non-steroidal phosphate compounds have now shown that the best inhibitors contain phosphate mono anions and that the basic structure for inhibition does not require the steroid nucleus. ... 

The year s reviews cover phosphorylated indoles, phosphorus-selenium compounds, phosphoryl carbenes, phosphorus-sulphur compounds, and steroid phosphates, as well as the synthesis of phosphorus esters via oxyphosphoranes. A review on phosphonates contains many interesting applications of some of the well-tried syntheses of these as analogues of natural phosphates. ... 

The naturally occurring cardenolides and the functions and chemistry of insect moulting hormones have been reviewed. The synthesis of steroid phosphates, sulphates, and glycosides has been summarised in a new book which draws attention to inadequacies in the current Rules of Carbohydrate Nomenclature when two types of glycosidic linkages are present, and in which is proposed a modification of these rules applicable to steroid glycosides. 

High Performance Liquid Chromatography.—This technique has been applied to a wide range of natural products, i.e., steroidal phosphates, retinyl phosphate, dansylated protein hydrolysates, thiamine phosphates, dibutyl c-AMP esters, cytosine arabinoside triphosphate, and di- and tri-nucleoside phosphates. ... 

Negatively Charged Pharmaceuticals Delivered by Positively Charged Polymers Consideration of Steroid Phosphates and Oligonucleotides... 

Harvey, D.J., Homing, M.G., and Vouros, P. (1971) Some stereochemical factors in the formation of rearrangement ions in the mass spectra of trimethylsilyl derivatives of steroidal phosphates. Tetrahedron, 27,4231-4243. 

Three hormones regulate turnover of calcium in the body (22). 1,25-Dihydroxycholecalciferol is a steroid derivative made by the combined action of the skin, Hver, and kidneys, or furnished by dietary factors with vitamin D activity. The apparent action of this compound is to promote the transcription of genes for proteins that faciUtate transport of calcium and phosphate ions through the plasma membrane. Parathormone (PTH) is a polypeptide hormone secreted by the parathyroid gland, in response to a fall in extracellular Ca(Il). It acts on bones and kidneys in concert with 1,25-dihydroxycholecalciferol to stimulate resorption of bone and reabsorption of calcium from the glomerular filtrate. Calcitonin, the third hormone, is a polypeptide secreted by the thyroid gland in response to a rise in blood Ca(Il) concentration. Its production leads to an increase in bone deposition, increased loss of calcium and phosphate in the urine, and inhibition of the synthesis of 1,25-dihydroxycholecalciferol. 

Generally, NAD-linked dehydrogenases catalyze ox-idoreduction reactions in the oxidative pathways of metabolism, particularly in glycolysis, in the citric acid cycle, and in the respiratory chain of mitochondria. NADP-linked dehydrogenases are found characteristically in reductive syntheses, as in the extramitochon-drial pathway of fatty acid synthesis and steroid synthesis—and also in the pentose phosphate pathway. 

The pentose phosphate pathway is an alternative route for the metabolism of glucose. It does not generate ATP but has two major functions (1) The formation of NADPH for synthesis of fatty acids and steroids and (2) the synthesis of ribose for nucleotide and nucleic acid formation. Glucose, fructose, and galactose are the main hexoses absorbed from the gastrointestinal tract, derived principally from dietary starch, sucrose, and lactose, respectively. Fructose and galactose are converted to glucose, mainly in the liver. 

Pyridoxal phosphate is a coenzyme for many enzymes involved in amino acid metabolism, especially in transamination and decarboxylation. It is also the cofactor of glycogen phosphorylase, where the phosphate group is catalytically important. In addition, vitamin Bg is important in steroid hormone action where it removes the hormone-receptor complex from DNA binding, terminating the action of the hormones. In vitamin Bg deficiency, this results in increased sensitivity to the actions of low concentrations of estrogens, androgens, cortisol, and vitamin D. 

Vitamin A (retinol), present in carnivorous diets, and the provitamin (P-carotene), found in plants, form retinaldehyde, utilized in vision, and retinoic acid, which acts in the control of gene expression. Vitamin D is a steroid prohormone yielding the active hormone derivative calcitriol, which regulates calcium and phosphate metaboUsm. Vitamin D deficiency leads to rickets and osteomalacia. 

Phosphorylation of cholesterol followed by the normal hydrolytic work-up gives the phosphate monoester, not the symmetrical pyrophosphate diester as previously claimed. Cholesteryl phosphorodichloridate and some related steroidal phosphorodichloridates have been prepared from the action of pyrophosphoryl chloride on the appropriate alcohol ... 

Trichloroethylene 1.9 OS-phosphate buffer pH 7 (2/1) 20 /S-Hydroxy steroid dehydrogenase... 

The steroids aldosterone, cortisone, cortisol, 11-P-hydroxyandrostenedione, corticosterone, and rostenedione, 11-desoxycorticosterone, 17-hydroxy-progesterone, and progesterone have been performed on Ultrasphere ODS using methanokwater.19 Ranitidine N-[2-[[[5-[(dimethylamino)methyl]-2-furanyl]-methyl]thio]ethyl]-N1-methyl-2-nitro-l,l-ethenediamine has been separated using a p-Bondapak C18 column operated with acetoni-trile methanol water buffered with triethylamine phosphate.117 Pyridoxal-5 -phosphate and other B6 vitamers, including pyridoxamine phosphate, pyri-doxal, pyridoxine, and 4-pyridoxic acid, were separated as bisulfite adducts... 

Suspension. If the drug is not sufficiently soluble, it can be formulated as a suspension. A suspension may also be desired to improve stability, bioavailability, or efficacy. The major topical ophthalmic suspensions are the steroid anti-inflammatory agents prednisolone acetate, dexamethasone, fluorometholone, and rimex-olone. Water-soluble salts of prednisolone phosphate and dexamethasone phosphate are available however, they have a lower steroid potency and are poorly absorbed. 

Treatment of hemolytic anemia should focus on correcting the underlying cause. There is no specific therapy for glucose-6-phosphate dehydrogenase deficiency, so treatment consists of avoiding oxidant medications and chemicals. Steroids, other immunosuppressants, and even splenectomy can be indicated to reduce RBC destruction. 

Robertson JA, Bhattacharyya S, Ing NH (1998) Tamoxifen up-regulates oestrogen receptor-alpha, c-fos and glyceraldehyde 3-phosphate-dehydrogenase mRNAs in ovine endometrium. J Steroid Biochem Mol Biol 67(4) 285-292... 

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