In vitro 19-norandrogen synthesis by equine placenta requires the participation of aromatase

1995 ◽  
Vol 144 (3) ◽  
pp. 517-525 ◽  
Author(s):  
S Moslemi ◽  
P Silberzahn ◽  
J-L Gaillard
Keyword(s):  
Silica Gel ◽  
Aromatase Inhibitors ◽  
Column Chromatography ◽  
Microsomal Fraction ◽  
Specific Activity ◽  
Reverse Phase Hplc ◽  
Reverse Phase ◽  
Term Placenta ◽  
Flow Detector

Abstract Explants of equine full-term placenta have been shown to synthesize 19-norandrogens from labelled androgens. Steroid metabolites were purified by silica-gel column chromatography then analysed and quantified by C18-reverse-phase HPLC coupled to a radioactive flow detector. 19-Norandrostenedione was subsequently recrystallized to constant specific activity, providing unequivocal evidence of its synthesis by the equine placenta. 19-Norandrostenedione synthesis appeared to be localized in the microsomal fraction. Regardless of the substrate used, formation of 19-norandrogens was far weaker than that of oestrogens; moreover, the yield of 17-oxosteroids produced was much greater than that of 17β-hydroxysteroids, suggesting the presence of a dehydrogenase with predominant oxidative activity. Sulphoconjugated steroids formed were less than 0·5% of total steroids. Although 19-nortestosterone could not be generated by equine purified aromatase incubated with labelled testosterone, the synthesis of 19-norandrogens and oestrogens by equine placental explants was blocked by two specific aromatase inhibitors, 4-hydroxyandrostenedione and fadrozole. Our results provide evidence for a placental origin of at least a part of the 19-norandrogens previously identified in the blood of the pregnant mare. Furthermore, it is suggested that 19-norandrogen biosynthesis would involve the enzymatic metabolism of 19-oxygenated androgens formed by equine aromatase. Journal of Endocrinology (1995) 144, 517–525

scholarly journals Sequestration of Stigmasterol and β-Sitosterol from Ethanolic Extract of Kam Sabut (Croton caudatus Geiseler) Leaves

2021 ◽  
Vol 33 (11) ◽  
pp. 2851-2856
Author(s):  
Longjam Shantabi ◽  
Ganesh Chandra Jagetia ◽  
Sharubam Victoria Devi ◽  
H. Lalhenmawia ◽  
Raghuvir H. Gaonkar
Keyword(s):  
Anticancer Activity ◽  
Mass Spectroscopy ◽  
Column Chromatography ◽  
Hela Cells ◽  
Ethanolic Extract ◽  
Reverse Phase Hplc ◽  
Reverse Phase ◽  
Northeastern India ◽  
First Time

Croton caudatus (Kam sabut) has been traditionally used to treat cancer in northeastern India and earlier studies reported the anticancer activity of ethanolic extract of C. caudatus leaves in HeLa cells in vitro and Swiss albino mice transplanted with Dalton’s ascites lymphoma. Therefore, isolation of stigmasterol and β-sitosterol from the ethanolic extract of C. caudatus Geiseler leaves was carried out. Stigmasterol and β-sitosterol were isolated from the ethanolic extract of dried leaves of C. caudatus by column chromatography. The fractions were purified further on Sephadex® LH-20 column chromatography and reverse-phase HPLC. The isolated phytosterols were characterized and quantified by IR, 1H & 13 CNMR, mass spectroscopy and HPLC. This has led to the separation of 100 mg stigmasterol and 80 mg β-sitosterol. Stigmasterol and β-sitosterol have been isolated from the ethanolic extract of C. caudatus leaves for the first time.

Conversion of Flavanone to Flavone, Dihydroflavonol and Flavonol with an Enzyme System from Cell Cultures of Parsley

1981 ◽  
Vol 36 (9-10) ◽  
pp. 742-750 ◽  
Author(s):  
L. Britsch ◽  
W. Heller ◽  
H. Grisebach
Keyword(s):  
Microsomal Fraction ◽  
Specific Activity ◽  
Enzyme System ◽  
High Specific Activity ◽  
Cell Suspension Cultures ◽  
Soluble Enzyme ◽  
Enzyme Preparations ◽  
Malonyl Coa ◽  
In Vitro Biosynthesis

Abstract Soluble enzyme preparations from irradiated cell suspension cultures of parsley (Petroselinum hortense Hoffm.) catalyse the conversion of flavanone to flavone, dihydroflavonol and flavonol. These reactions require 2-oxoglutarate, Fe2+ and ascorbate as cofactors. In the presence of these cofactors conversion of dihydroflavonol to flavonol was also observed. With this system in vitro biosynthesis of radioactive flavone, dihydroflavonol and flavonol from [2-14C]malonyl-CoA and 4-coumaroyl-CoA in good yield and with high specific activity is possible.We postulate that synthesis of flavone and flavonol from flavanone proceeds via 2-hydroxy-and 2,3-dihydroxyflavanone, respectively, with subsequent dehydration.The microsomal fraction of the parsley cells contains an NADPH-dependent flavanone 3'-hydroxylase.

scholarly journals The effect of phenobarbital on the submicrosomal distribution of uridine diphosphate glucuronyltransferase from rat liver

1970 ◽  
Vol 117 (2) ◽  
pp. 319-324 ◽  
Author(s):  
G. J. Mulder
Keyword(s):  
Enzyme Activity ◽  
Density Gradient ◽  
Rat Liver ◽  
Microsomal Fraction ◽  
Specific Activity ◽  
Sucrose Density Gradient ◽  
Male Rats ◽  
Uridine Diphosphate ◽  
Triton X

1. The detergent Triton X-100 activates UDP glucuronyltransferase from rat liver in vitro six- to seven-fold with p-nitrophenol as substrate. The enzyme activity when measured in the presence of Triton X-100 is increased significantly by pretreatment of male rats with phenobarbital for 4 days (90mg/kg each day intraperitoneally). If no Triton X-100 is applied in vitro such an increase could not be shown. In all further experiments the enzyme activity was measured after activation by Triton X-100. 2. The Km of the enzyme for the substrate p-nitrophenol does not change on phenobarbital pretreatment. 3. When the microsomal fraction from the liver of untreated rats is subfractionated on a sucrose density gradient, 47% of the enzyme activity is recovered in the rough-surfaced microsomal fraction, which also has a higher specific activity than the smooth-surfaced fraction. 4. Of the increase in activity after the phenobarbital pretreatment 50% occurs in the smooth-surfaced fraction, 19% in the rough-surfaced fraction and 31% in the fraction located between the smooth- and rough-surfaced microsomal fractions on the sucrose density gradient. 5. The latency of the enzyme in vitro, as shown by the effect of the detergent Triton X-100, is discussed in relation to the proposed heterogeneity of UDP glucuronyltransferase.

scholarly journals Biogenesis of mitochondria. Phospholipid synthesis in vitro by yeast mitochondrial and microsomal fractions

1974 ◽  
Vol 144 (2) ◽  
pp. 265-275 ◽  
Author(s):  
G S Cobon ◽  
P D Crowfoot ◽  
A W Linnane
Keyword(s):  
Phosphatidic Acid ◽  
Microsomal Fraction ◽  
De Novo ◽  
Specific Activity ◽  
Neutral Lipids ◽  
Mitochondrial Fraction ◽  
Biogenesis Of Mitochondria ◽  
Glycerolipid Synthesis ◽  
Phosphatidylcholine Synthesis

The ability in vitro of yeast mitochondrial and microsomal fractions to synthesize lipid de novo was measured. The major phospholipids synthesized from sn-[2-3H]glycerol 3-phosphate by the two microsomal fractions were phosphatidylserine, phosphatidylinositol and phosphatidic acid. The mitochondrial fraction, which had a higher specific activity for total glycerolipid synthesis, synthesized phosphatidylglycerol, phosphatidylethanolamine, phosphatidylinositol, phosphatidylserine and phosphatidic acid, together with smaller amounts of neutral lipids and diphosphatidylglycerol. Phosphatidylcholine synthesis from both S-adenosyl[Me-14C]methionine and CDP-[Me-14C]choline appeared to be localized in the microsomal fraction.

Validation and application of a simple reverse phase HPLC method for in vitro dissolution studies of memantine hydrochloride tablet

2015 ◽  
Vol 45 (5) ◽  
pp. 415-421 ◽  
Author(s):  
Han-Joo Maeng ◽  
Sung-Up Choi ◽  
Dong-Jin Jang ◽  
Dong Won Lee ◽  
Byung-Nak Ahn ◽  
...  
Keyword(s):  
Hplc Method ◽  
In Vitro Dissolution ◽  
Reverse Phase Hplc ◽  
Reverse Phase ◽  
Dissolution Studies

scholarly journals Triterpenoids from the wood of Willughbeia cochinchinensis

2018 ◽  
Vol 1 (T5) ◽  
pp. 137-142
Author(s):  
Linh Thi My Lam ◽  
Phu Hoang Dang ◽  
Hai Xuan Nguyen ◽  
Nhan Trung Nguyen ◽  
Mai Thi Thanh Nguyen
Keyword(s):  
Thin Layer ◽  
Ethyl Acetate ◽  
Thin Layer Chromatography ◽  
Silica Gel ◽  
Column Chromatography ◽  
Normal Phase ◽  
Reverse Phase ◽  
Chemical Structures ◽  
First Time ◽  
Layer Chromatography

From the wood of n-hexane extract of Willughbeia cochinchinensis, perform column chromatography on a normal phase silica gel with n-hexane: ethyl acetate obtained in 8 fractions. From GD-D and GD-F fractions, multiple column chromatography on silica gel was performed in combination with normal and reverse phase thin-layer chromatography, four triterpene compounds as epifriedelanol (1), taraxeryl acetate (2), ambolic acid (3) and α- amyrin (4) were isolated. Their chemical structures were determined by spectrocopic methods as well as comparing with data in the literature. These compounds were isolated for the first time from Willughbeia cochinchinensis.

scholarly journals IN VITRO ANTIPLASMODIAL ACTIVITY OF FLOWER EXTRACTS FROM COMBRETUM LEPROSUM MART (MOFUMBO)

2016 ◽  
Vol 39 (1) ◽  
pp. 84 ◽  
Author(s):  
Guilherme Matos Passarini ◽  
Daniel Sol Medeiros ◽  
Dionatas Ulisses de Oliveira Meneguetti ◽  
Renato Abreu Lima ◽  
Valdir Alves Facundo ◽  
...  
Keyword(s):  
At Risk ◽  
Silica Gel ◽  
Column Chromatography ◽  
Chloroform Extract ◽  
Antiplasmodial Activity ◽  
Pharmacological Studies ◽  
Combretum Leprosum ◽  
Resistant Strains ◽  
Active Substances

Malaria is the cause of hundreds of deaths per year , besides putting billions of people at risk of developing disease. When it comes to its therapy, the drugs used currently are losing its efficacy due to increase inn the frequency of resistant strains of the parasite, highlight the importance for the serach of new classes of molecules prsentign antiplasmodial activity. In the present work, the antiplasmodial activities of five extracts from the flowers of Comretum leprosum are described. The method employed for obtaingine the extracts was silica gel column chromatography, and the techniques used for the analysis of antiplasmodial activity and citotoxicity were ELISA and MTT respectively, were a selectivitu index was calculated after the obtainign of these two values. The extract presenting the highest antiplasmodial activity was the chloroform extract, however, this extrac also presented the higther cytotoxicity and therefore the extract presenting the best overall activity was the hexane extract. The study deminstrated the plant Combretum leprosum has active substances against P. falciparum and therefore is a potential to be expored in funther pharmacological studies.

scholarly journals Analysis of long dsRNA produced in vitro and in vivo using atomic force microscopy in conjunction with ion-pair reverse-phase HPLC

The Analyst ◽  
2019 ◽  
Vol 144 (16) ◽  
pp. 4985-4994
Author(s):  
Alison O. Nwokeoji ◽  
Sandip Kumar ◽  
Peter M. Kilby ◽  
David E. Portwood ◽  
Jamie K. Hobbs ◽  
...  
Keyword(s):  
Atomic Force Microscopy ◽  
High Performance ◽  
Ion Pair ◽  
Reverse Phase Hplc ◽  
Reverse Phase ◽  
Force Microscopy ◽  
Atomic Force ◽  
Insight Into

Atomic force microscopy (AFM) in conjunction with ion-pair reverse-phase high performance liquid chromatography (IP-RP-HPLC) provides novel insight into dsRNA for RNAi applications.

scholarly journals Biotransformation of Cholesterol and 16α,17α-Epoxypregnenolone and Isolation of Hydroxylase inBurkholderia cepaciaSE-1

2016 ◽  
Vol 2016 ◽  
pp. 1-8 ◽  
Author(s):  
XiangDong Zhu ◽  
CuiPing Pang ◽  
Yuting Cao ◽  
Dan Fan
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Bile Acids ◽  
Steroid Hormones ◽  
Silica Gel ◽  
Mass Spectroscopy ◽  
Column Chromatography ◽  
Burkholderia Cepacia ◽  
Specific Activity ◽  
Biotransformation Products

The metabolism of cholesterol is critical in eukaryotes as a precursor for vitamins, steroid hormones, and bile acids. Some steroid compounds can be transformed into precursors of steroid medicine by some microorganisms. In this study, the biotransformation products of cholesterol and 16α,17α-epoxypregnenolone produced byBurkholderia cepaciaSE-1 were investigated, and a correlative enzyme, hydroxylase, was also studied. The biotransformation products, 7β-hydroxycholesterol, 7-oxocholesterol, and 20-droxyl-16α,17α-epoxypregn-1,4-dien-3-one, were purified by silica gel and Sephadex LH-20 column chromatography and identified by nuclear magnetic resonance and mass spectroscopy. The hydroxylase was isolated from the bacterium and the partial sequences of the hydroxylase, which belong to the catalases/peroxidase family, were analyzed using MS/MS analyses. The enzyme showed activity toward cholesterol and had a specific activity of 37.2 U/mg of protein at 30°C and pH 7.0.

PATHWAYS FOR ANDROGEN SYNTHESIS IN VITRO BY THE TESTES OF JAPANESE QUAIL (COTURNIX COTURNIX JAPONICA)

1972 ◽  
Vol 55 (3) ◽  
pp. 499-506 ◽  
Author(s):  
TAKAO NAKAMURA ◽  
YUICHI TANABE
Keyword(s):  
Japanese Quail ◽  
Microsomal Fraction ◽  
Specific Activity ◽  
Testicular Tissue ◽  
Coturnix Japonica ◽  
Coturnix Coturnix Japonica ◽  
Coturnix Coturnix ◽  
Androgen Synthesis ◽  
Metabolic Products

SUMMARY The microsomal fraction of testicular tissue from Japanese quail (Coturnix coturnix japonica) was incubated with 4-14C-labelled pregnenolone, progesterone, 17α-hydroxyprogesterone, androstenedione, dehydroepiandrosterone and testosterone and [7-3H]17α-hydroxypregnenolone in a medium containing either NAD or NADPH. The metabolic products were identified by their mobilities on thin-layer chromatograms, derivative formation after oxidation and acetylation of the metabolites, and recrystallization to constant specific activity. Three pathways for testosterone formation by the testes are suggested by the results: the first via progesterone, 17α-hydroxyprogesterone and androstenedione; the second via 17α-hydroxypregnenolone, dehydroepiandrosterone and androstenedione; and the third via 17α-hydroxypregnenolone, dehydroepiandrosterone and androst-5-ene-3β,17β-diol.

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