Direct Conversion of 17β-Estradiol-3-ghicosiduronate and 17β-Estradiol-3-sulfate to their 17-Keto Forms by Human Kidney Homogenates

1974 ◽  
Vol 52 (1) ◽  
pp. 15-20 ◽  
Author(s):  
R. Hobkirk ◽  
R. N. Green ◽  
M. Nilsen ◽  
B. A. Jennings
Keyword(s):  
Human Kidney ◽  
Direct Conversion ◽  
Reverse Reaction ◽  
Experimental Conditions ◽  
Glucuronidase Activity ◽  
Sulfatase Activity ◽  
17Β Estradiol ◽  
Low Activity

Labelled 17β-estradiol-3-glucosiduronate and 17β-estradiol-3-sulfate were both directly dehydrogenated to their respective 17-keto forms on incubation with human kidney homogenates. NAD increased the conversion to a greater extent than did NADP. The reverse reaction, even in the presence of NADH or NADPH was not found to a measurable extent, presumably because of rapid oxidation of the cofactors. High or low activity towards the conjugates was accompanied by high or low activity, respectively, towards free 17β-estradiol. These dehydrogenase activities were particularly high in the medulla of one kidney so investigated. Considerable sulfatase activity was usually encountered in these homogenates but little β-glucuronidase activity was demonstrated under the experimental conditions.

17-Oxidoreduction of 17β-Estradiol, Estrone and Their 3-Sulfates by Kidney Slices from Guinea Pig and Human

1975 ◽  
Vol 53 (12) ◽  
pp. 1333-1336 ◽  
Author(s):  
R. Hobkirk ◽  
Mona Nilsen ◽  
Barbara Jennings
Keyword(s):  
Guinea Pig ◽  
Marked Reduction ◽  
Human Kidney ◽  
Kidney Cortex ◽  
Limited Extent ◽  
Tissue Slices ◽  
Ample Evidence ◽  
Sulfatase Activity ◽  
17Β Estradiol ◽  
Dehydrogenation Reactions

Slices of whole kidney and kidney cortex from the female guinea pig catalyzed a marked reduction of estrone 3-sulfate (E13S) and estrone (E1) to 17β-estradiol 3-sulfate (E23S) and 17β-estradiol (E2), respectively, as well as the reverse (dehydrogenation) reactions. Slices of medulla did not appear active in E23S–E13S interconversion but did possess the ability to interconvert E2 and E1, besides possessing considerable sulfatase activity. The use of [3H-35S]E13S and [3H-35S]E23S as substrates, together with a demonstrated lack of estrogen sulfate synthesis by the tissue slices, provided ample evidence that the intact sulfates were involved in direct oxidoreduction. Slices of human kidney cortex catalyzed the reduction of E13S to a very limited extent. Slices of whole kidney and of cortex from guinea pig formed small amounts of estrogen glucuronide(s).

Formation of Estrogen Glucosiduronates by Human Kidney Homogenates

1974 ◽  
Vol 52 (1) ◽  
pp. 9-14 ◽  
Author(s):  
R. Hobkirk ◽  
R. N. Green ◽  
M. Nilsen ◽  
B. A. Jennings
Keyword(s):  
Human Kidney ◽  
Kidney Cortex ◽  
Partition Chromatography ◽  
Experimental Conditions ◽  
17Β Estradiol ◽  
Acid Metabolites ◽  
Steroid Conjugates

17β-Estradiol-6,7-3H (E2), 17β-estradiol-6,7-3H-3-sulfate (E23S), and estriol-6,7-3H (E3) were each incubated with human kidney homogenates in the presence of uridine diphosphoglucuronic acid. Metabolites were purified by DEAE-Sephadex and Celite partition chromatography and were identified by crystallization with carrier steroid conjugates and free steroids. E2 was converted to a small but definite extent (< 0.1–5%) to estrone-3-glucosiduronate, 17β-estradiol-3-glucosiduronate, and 17β-estradiol-17-glucosiduronate, the latter conjugate usually predominating. Under the experimental conditions E2 was a better precursor of all three conjugates than was E23S. In one experiment where kidney cortex and medulla were incubated separately with E2, the former was some 20 times more efficient in glucosiduronate synthesis. E3 was converted to the extent of 52–91% to estriol-16-glucosiduronate by whole kidney homogenates.

scholarly journals Inhibitory effect of t-butyl hydroperoxide on mitochondrial oxidative phosphorylation in isolated rat hepatocytes

2007 ◽  
pp. 137-140
Author(s):  
P Křiváková ◽  
A Lábajová ◽  
Z Červinková ◽  
Z Drahota
Keyword(s):  
Oxidative Phosphorylation ◽  
Rat Hepatocytes ◽  
Inhibitory Effect ◽  
Experimental Conditions ◽  
Isolated Rat Hepatocytes ◽  
Butyl Hydroperoxide ◽  
Peroxidative Damage ◽  
Cell Energy ◽  
Uncoupling Of Oxidative Phosphorylation ◽  
Low Activity

Using high-resolution oxygraphy, we tested the changes of various parameters characterizing the mitochondrial energy provision system that were induced by peroxidative damage. In the presence of succinate as respiratory substrate, 3 mM t-butyl hydroperoxide increased respiration in the absence of ADP, which indicated partial uncoupling of oxidative phosphorylation. Low activity of coupled respiration was still maintained as indicated by the ADP-activated and oligomycin-inhibited respiration. However, during the incubation the phosphorylative capacity decreased as indicated by the continuous decrease of the mitochondrial membrane potential. Under these experimental conditions the maximum capacity of the succinate oxidase system was inhibited by 50% in comparison with values obtained in the absence of t-butyl hydroperoxide. Our data thus indicate that the oxygraphic evaluation of mitochondrial function represents a useful tool for evaluation of changes participating in peroxidative damage of cell energy metabolism.

OESTROGEN METABOLISM IN THE HUMAN FOETUS

1961 ◽  
Vol 37 (4) ◽  
pp. 516-528 ◽  
Author(s):  
E. Diczfalusy ◽  
O. Cassmer ◽  
C. Alonso ◽  
M. de Miquel ◽  
B. Westin
Keyword(s):  
Placental Tissue ◽  
Elevated Concentration ◽  
Human Foetus ◽  
Experimental Conditions ◽  
Foetal Liver ◽  
17Β Estradiol ◽  
Distribution Studies

ABSTRACT In vitro and in vivo experiments were carried out in order to test a previously advanced hypothesis according to which the human foetus is capable of carrying out oestrogen conjugation reactions. In vitro incubation of slices of different foetal tissues with oestriol (oestra-1,3,5(10)-triene-3,16α,17β-triol) resulted in a significantly increased concentration of conjugated oestriol in foetal liver, lungs, kidneys, adrenals, and perhaps also in skeletal muscle. No such increase was found when endometrial or myometrial tissue from an adult subject was incubated under the same experimental conditions, or when foetal tissues were incubated in the absence of oestriol. Countercurrent distribution studies of the conjugated material formed in vitro suggest that it might be identical with oestriol Intra-amniotic injection of 17β-estradiol ((oestra-1,3,5(10))-triene-3,17βdiol) or oestriol to volunteers in whom the foetus was previously separated in situ from its placental connections resulted in a significantly elevated concentration of conjugated oestrone ((3-hydroxy-oestra-1,3,5(10)-trien17-one). 17β-oestradiol and oestriol, respectively, in the foetal lungs and livers and – following 17β administration – also in the intestines. On the other hand, the concentration of conjugated oestrone, 17β-oestradiol or oestriol in the placental tissue was significantly lower under these conditions than in similarly treated patients with an intact foeto-placental connection. When previable foetuses were perfused with diluted blood to which 17β-oestradiol, or oestriol was added, a significantly elevated concentration of conjugated oestrone + 17β-oestradiol, and oestriol, respectively, was found in the foetal lungs, liver, intestines, kidneys + adrenals. It is concluded that the human foetus is already an important site of oestrogen conjugation at relatively early stages of gestation. It is suggested that these conjugation processes take place in several foetal organs, such as the lungs, liver, kidneys, adrenals, intestines, and perhaps also other tissues.

Fate of nonylphenol and 17β-estradiol contained in composted sewage sludge after land application

2008 ◽  
Vol 57 (2) ◽  
pp. 167-174 ◽  
Author(s):  
M. Minamiyama ◽  
S. Ochi ◽  
Y. Suzuki
Keyword(s):  
Sewage Sludge ◽  
Early Stage ◽  
Soil Layer ◽  
Land Application ◽  
Experimental Conditions ◽  
17Β Estradiol ◽  
High Concentrations ◽  
Biological Decomposition ◽  
Composted Sewage Sludge ◽  
Composted Sludge

Many environmental problems caused by endocrine disrupters (EDs) have been reported. Because little is known about the fate of EDs accumulated in sewage sludge, we carried out a study to clarify the fate of EDs in composted sludge after its application to soil. Nonylphenol (NP) and 17β-estradiol (E2) were measured for leachate and soil. High concentrations of NP and E2 were detected in the leachate at the early stage, but they decreased rapidly. Also, the high contents of NP and E2 in soil decreased significantly within 300 days. Because the decrease of NP and E2 in the soil was much larger than that of NP and E2 in the leachate, there must have been a physicochemical or biological decomposition mechanism in the soil layer. We also tried to clarify the transfer of NPs to plants from compost. In the experimental conditions of this study, the transfer of NPs to plants from compost was not observed.

Effects of 17β-estradiol on typical greenhouse gas emissions in aquatic anaerobic ecosystem

2015 ◽  
Vol 71 (12) ◽  
pp. 1815-1822
Author(s):  
Aidong Ruan ◽  
Chenxiao Liu ◽  
Ying Zhao ◽  
Fengjiao Zong ◽  
Shaopeng Jiang ◽  
...  
Keyword(s):  
Greenhouse Gases ◽  
Greenhouse Gas ◽  
Microbial Populations ◽  
Experimental Conditions ◽  
Methanogenic Activity ◽  
Ch4 Production ◽  
17Β Estradiol ◽  
Micro Organisms ◽  
The Relationship ◽  
Estradiol 17Β

Anaerobic microecosystems designed with different concentrations of 17β-estradiol (17β-E2) (0.0–10,000.0 ng/L) were simulated in this study. The influence of different concentrations of 17β-E2 on the emissions of typical greenhouse gases (CH4 and CO2) in simulated anaerobic microecosystems is analyzed to primarily explore the relationship between 17β-E2 and such emissions in aquatic anaerobic ecosystems. The results showed that 17β-E2 could promote or significantly stimulate aquatic anaerobic micro-organisms' production of CH4. The degree and the promotion time of CH4 production were both enhanced with the increase of 17β-E2 concentration. Furthermore, under higher concentration of 17β-E2 (≥500.0 ng/L), the increasing tendency of aquatic anaerobic microbial populations' activity and the function of methanogenic activity under corresponding experimental conditions had a synchronous relationship.

scholarly journals Metabolism of Dehydroepiandrosterone Sulfate and Estrone-Sulfate by Human Platelets

2012 ◽  
pp. 381-388 ◽  
Author(s):  
A. GARRIDO ◽  
Y. MUÑOZ ◽  
W. SIERRALTA ◽  
L. VALLADARES
Keyword(s):  
Organic Anion ◽  
Dehydroepiandrosterone Sulfate ◽  
Human Platelets ◽  
Steroid Sulfatase ◽  
Organic Anion Transporting Polypeptide ◽  
Estrone Sulfate ◽  
High Affinity ◽  
Sulfatase Activity ◽  
17Β Estradiol ◽  
Estrone Sulphate

The aim of the present research was to study the uptake of DHEAS, and to establish the intracrine capacity of human platelets to produce sex steroid hormones. The DHEAS transport was evaluated through the uptake of [3H]-DHEAS in the presence or absence of different substrates through the organic anion transporting polypeptide (OATP) family. The activity of sulfatase enzyme was evaluated, and the metabolism of DHEAS was measured by the conversion of [3H]-DHEAS to [3H]-androstenedione, [3H]-testosterone, [3H]-estrone and [3H]-17β-estradiol. Results indicated the existence in the plasma membrane of an OATP with high affinity for DHEAS and estrone sulphate (E1S). The platelets showed the capacity to convert DHEAS to active DHEA by the steroid-sulfatase activity. The cells resulted to be a potential site for androgens production, since they have the capacity to produce androstenedione and testosterone; in addition, they reduced [3H]-estrone to [3H]-17β-estradiol. This is the first demonstration that human platelets are able to import DHEAS and E1S using the OATP family and to convert DHEAS to active DHEA, and to transform E1S to 17β-estradiol.

Equilibrium reactions of n-butanethiol with some conjugated heteroenoid compounds

1968 ◽  
Vol 46 (5) ◽  
pp. 775-781 ◽  
Author(s):  
R. B. Pritchard ◽  
C. E. Lough ◽  
D. J. Currie ◽  
H. L. Holmes
Keyword(s):  
Functional Group ◽  
Equilibrium Constants ◽  
Phenyl Group ◽  
Reverse Reaction ◽  
Experimental Conditions ◽  
Standard Methods ◽  
Conjugated Systems ◽  
Equilibrium Reactions ◽  
Measurable Rate

The reactions of 2-benzal-1,3-indanediones and the cyano-containing benzalmalononitriles, ethyl benzalcyanoacetates, benzalcyanoacetamides, and benzalcyanoacetanilides with n-butanethiol at 25 °C in 20% ethanol – 80% pH 7 buffer attain equlibrium at a rate too fast to measure by standard methods. The equilibrium constants have been calculated and these in turn related to Hammett σ and Taft σ* constants. The differences in the reactions of these and other gem difunctional systems which react virtually completely with n-butanethiol under the same experimental conditions and at a measurable rate, are attributed to participation of the functional group cis to the phenyl group in the reverse reaction. It is shown that n-butanethiol adds to cinnamalacetophenone by a 1,4-mechanism and the reactions of this nucleophile with similar compounds having extended conjugated systems are discussed.

Sign in / Sign up

Export Citation Format

Share Document