Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0338671 (Steroids)
 9,479 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A synthesis of 1alpha-hydroxyergocalciferol (1alpha-hydroxyvitamin D2, a potent analog of vitamin D2, is described. The preparation route involves conversion of ergosterol in two steps (60%) to the known ergosta-4, 6, 22-trien-3-one and dehydrogenation of the triene with SeO2 to ergosta-1,4,6,22-tetraen-3-one (30%). Epoxidation of the tetraenone to the corresponding 1alpha, 2alpha-epoxide followed by Li/NH3 reduction gave ergosta-5,22-diene-1alpha, 3beta-diol in 26% yield from the tetranone. After conversion to the corresponding diacetate and allylic bromination/dehydrobromination 1alpha-acetoxyergosteryl acetate was obtained. Irradiation of this intermediate gave the previtamin which was converted to the new vitamin analog by thermal equilibration and hydrolysis of the acetates. Charcteristic uv, nmr and mass spectral patterns confirmed the structure of the product.
Steroids 1977 Nov
PMID:Synthesis of 1alpha-hydroxyergocalciferol. 30 45

A few pregnane derivatives were synthesized from 1,2-dehydroprogesterone (1). Ring A of 1,2-dehydroprogesterone was aromatized without affecting C-20, and the resulting acetoxy compound (2) after hydrolysis yielded 1-hydroxy-4-methyl-19-norpregna-1,3,5(10)-trien-20-one (3). Reactions of the phenol (3) with alkyl halides yielded the ethers 6a-6b and 7. Opening of the oxirane ring in 7 with secondary amines furnished the aminoalcohols 8a-8b. Friedelcraft's reaction of 3 with maleic anhydride and chloracetyl chloride led to the formation of 9 and 10, respectively. Base-catalyzed ring closure of 10 yielded 1-acetyl-12a-methyl-8-oxo-5[H]-1,2,3,3a,3b,4,8,9,10b,11,12, 12a-dodecahydrocyclopenta (7,8)-phenanthro (3,4-b) furan (11), which reacted with aromatic aldehydes regioselectively to furnish 12a-12b. Reaction of 1 with triethylorthoformate in the presence of boron trifluoride etherate involved the participation of C-21, and the carbonyl at C-3 remained unaffected. The product 13 was identified as 21-[2-hydroxyvinyl]-21-norpregna-1,4-diene-3,20-dione. Reductive amination with sodium cyanoborohydride in the presence of ammonium acetate did not attack ring A and smoothly furnished the amine 14 which, on reaction with succinic anhydride, gave 20-succinamylpregna-1,4-dien-3-one (15).
Steroids 1991 Apr
PMID:Regioselective reactions of 1,2-dehydroprogesterone: syntheses of pregnane derivatives as possible contragestational agents. 187 84

Aromatase from human placenta has been purified to homogeneity (MW 55,000). Enzymatic activity can be reconstituted with reductase from pig liver in an aqueous buffer or after incorporation of the enzyme into liposomes. In both cases the enzyme converts androstenedione to estrone and testosterone to estradiol. Aromatase shows a typical CO-spectrum when reduced with dithionite and a type I spectral shift with both substrates. The NH2 terminal amino acid sequence is hydrophobic but shows no homology to that of other cytochromes P-450. Five cysteine peptides have been isolated by HPLC following tryptic digestion of the [14C]-carboxymethylated protein. Amino acid sequences of these peptides reveal that histidine is the carboxy-terminal amino acid of the protein and that significant homology exists with corresponding peptides from other cytochromes P-450. Unique oligonucleotides (62 and 30 MER) synthesized on the basis of a 45 amino acid sequence near the center of the molecular have been used to clone the aromatase gene from a cDNA expression library from human placenta in lambda gt11.
Steroids
PMID:Purification and characterization of aromatase from human placenta. 350 67

In order to develop a radioimmunoassay for the new progestagen dienogest (STS 557, 17 alpha-cyanomethyl-17 beta-hydroxy-estra-4,9-dien-3-one), bovine serum albumin (BSA) conjugates of STS 557-3-carboxymethyloxime and of STS 557-11-hemisuccinate were synthesized as antigens for the production of antisera. It was proved that an excess of isobutylchlorocarbonate in the coupling reaction using the "mixed anhydride method" results in an acylation of free NH2-groups in the BSA. By the immunization of rabbits with the STS 557-antigen-antisera of high specificity and affinity to STS 557 were produced. Endogenous steroids show no cross reaction with the STS 557-antisera. Steroids with a 17 alpha-CH2CN-group, being obtained by chemical synthesis or microbial transformation, compete with STS 557 for the binding positions of the antibodies to a different extent.
 ...
PMID:[Bovine serum albumin conjugates of the new progestagen dienogest, synthesis and immunogenic properties]. 379 51

While the intact male adult rats respond to LH with a predominant increase of testicular and plasma testosterone levels, the response to LH stimulation in animals treated with the LHRH agonist, [D-Ser(TBU) 6, des-Gly-NH2(10)] LHRH ethylamide is characterized by a major production of 5 alpha-androstane-3 alpha, 17 beta-diol. The marked increase of 5 alpha-androstane-3 alpha, 17 beta-diol levels in the presence of a 90% decrease of testosterone concentration strongly suggests that 5 alpha-reductase and 3 alpha-hydroxysteroid oxidoreductase activities are increased during testicular desensitization induced by treatment with the LHRH agonist.
Steroids 1980 Oct
PMID:Increased testicular 5 alpha-androstane-3 alpha, 17 beta-diol formation induced by treatment with [D-Ser (TBU) 6, des-Gly-NH2(10)] LHRH ethylamide in the rat. 625 33

In order to better understand the effects of LHRH administration on testicular function in adult rat, we compared the inhibitory effects of LH and LHRH analogue [D-Ser-(TBU)6, des-Gly-NH2(10)]LHRH ethylamide upon testicular steroidogenesis and LH, FSH and prolactin receptor contents. Administration of LH as well as LHRH analogue resulted in a marked decrease of LH receptor levels, accompanied by a blockage at the level of 17-hydroxylase activity. We have been able to demonstrate that multiple LH administration can achieve a testicular desensitization comparable to that observed after LHRH agonist treatment.
Steroids 1982 Dec
PMID:Comparative effects of LHRH agonist and ovine LH administration on testicular steroidogenesis in intact adult rat. 631 98

The effects of GnRH and a potent GnRH analogue (D-Ala6-des-gly-NH2-GnRH-ethylamide) on steroidogenesis in isolated preovulatory follicles of PMSG-treated immature rats were examined in short-term incubations and compared to the effect of LH. Steroids were analyzed by RIA. GnRH stimulated the accumulation of pregnenolone (2-fold), progesterone (4-fold), 20 alpha-OH-progesterone (38-fold), androstenedione (4-fold), testosterone (3-fold), and oestradiol-17 beta (2-fold) during a 6 h incubation. The time-course of stimulation was the same for each of the steroids analyzed, with a significant effect at 4 and 6 h, but not at 2 h of incubation. Dose-response curves were similar for each steroid, and the GnRH analogue and GnRH gave parallel curves with minimal effective concentrations being 1 and 10 ng/ml, respectively. The stimulatory effect of LH was more pronounced and rapid (2 h) than that of GnRH. During prolonged incubation (6-8 h) with GnRH or LH there was evidence for an inhibition of testosterone production, probably due to suppression of the C21-side chain cleavage enzyme. Thus, the qualitative response to GnRH on follicular steroidogenesis resembled that of LH in some but not all respects. The differences in time-course and maximal steroid secretion between GnRH and LH are compatible with different mechanisms of action in the follicle.
 ...
PMID:Effect of gonadotrophin releasing hormone upon the pattern of steroidogenesis in isolated preovulatory rat follicles. 636 67

In order to study both direct and pituitary-mediated mechanisms of action of the LHRH analogue [D-Ser(TBU)6, des-Gly-NH2(10)]LHRH ethylamide upon testicular steroidogenesis in adult rat, we compared the effects of the agonist when administered alone or concomitantly with an anti-LH serum to non-hypophysectomized rats. Testicular steroid contents and in vitro progesterone and testosterone metabolism were determined. Anti-LH serum administration was able to prevent 5 alpha-reductase stimulation by the agonistic peptide, but not the inhibition of 17-hydroxylase activity. These data suggest that modulation of 17-hydroxylase involves both direct and pituitary-mediated processes, while 5 alpha-reductase stimulation is mainly if not only due to a pituitary-mediated mechanism.
Steroids 1984 Jan
PMID:Study of the direct effect of LHRH agonist on testicular 17-hydroxylase and 5 alpha-reductase activities in non-hypophysectomized adult rats treated with an anti-luteinizing hormone serum. 639 49

Several 17 beta-carboxamide derivatives of natural and fluorinated glucocorticoids have been synthesized. The 17 beta-carboxylic derivatives were obtained by periodic acid oxidation of their side chains. They were then activated by N-hydroxybenzotriazole (HOBT) and coupled to several primary amines. Using this method eleven 17 beta-carboxamide derivatives have been prepared in good yields.
Steroids 1980 Mar
PMID:Synthesis of steroidal 17 beta-carboxamide derivatives. 737 21

An improved procedure for the syntheses of stereoisomeric 3,6-dihydroxy- and 6-hydroxy-5 alpha-cholanoic acids (and their methyl esters) is described. The principal reactions employed are those reported in the preceding paper of this series, with the commercially available hyodeoxycholic acid as starting material. The final step in the procedure is the reduction of the key 5 alpha C-6 ketones with either the stereoselective equatorial reagent, Li/NH3/MeOH, or the axial reagent, Zn(BH4)2. The results of analysis of the prepared 6-monohydroxylated and 3,6-dihydroxylated stereoisomers by thin-layer chromatographic, high performance liquid chromatographic and gas-liquid chromatographic mobilities, and 1H and 13C nuclear magnetic resonance spectra are discussed along with the data for the corresponding compounds in the 5 beta-series.
Steroids 1993 Aug
PMID:Potential bile acid metabolites. 20. A new synthetic route to stereoisomeric 3,6-dihydroxy- and 6-hydroxy-5 alpha-cholanoic acids. 821 86


1 2 3 Next >>