Inhibition of cytochrome P-450 C17 enzyme by a GnRH agonist in ovarian follicles from gonadotropin-stimulated rats

2007 ◽  
Vol 292 (5) ◽  
pp. E1456-E1464 ◽  
Author(s):  
Griselda Irusta ◽  
Fernanda Parborell ◽  
Marta Tesone
Keyword(s):  
Direct Action ◽  
Regulatory Protein ◽  
Follicular Development ◽  
Inhibitory Effect ◽  
Female Rats ◽  
Serum Progesterone ◽  
Protein Levels ◽  
Androgen Synthesis ◽  
Cytochrome P 450

Our objective was to study the direct action of a GnRH-I agonist, leuprolide acetate (LA), on ovarian steroidogenesis in preovulatory follicles obtained from equine chorionic gonadotropin (eCG)-treated rats. Previously, we have demonstrated an inhibitory effect of LA on steroidogenesis and follicular development. In this study, we tested the hypothesis that gonadotropin-releasing hormone (GnRH) exerts its negative effect on follicular development by inhibiting thecal cytochrome P-450 C17 (P450C17) α-hydroxylase expression and, consequently, androgen synthesis. Studies were carried out in prepubertal female rats injected with either eCG (control) or eCG plus LA (LA) and killed at different time points. Immunohistochemical studies indicated that LA induced steroidogenic acute regulatory protein (StAR) expression mainly in theca cells of preantral and antral follicles. In addition, serum progesterone levels increased significantly ( P < 0.05), whereas those of androsterone decreased ( P < 0.05) after 8 h of LA treatment. This inhibition caused by LA seemed to be a consequence of the decreased expression of follicular P450C17 α-hydroxylase, as demonstrated by Western blot and RT-PCR techniques. In vitro studies using follicles isolated from 48-h-eCG-treated rats and cultured with LA showed a significant ( P < 0.05) inhibition of FSH-induced androsterone follicular content as well as P450C17 α-hydroxylase protein levels, as determined by Western analysis. However, LA increased StAR protein expression in these follicles without significant changes in P450scc enzyme levels. Taking all these findings into account, we suggest that GnRH-I exerts a direct inhibitory action on gonadotropin-induced follicular development by decreasing the temporal expression of the P450C17 enzyme and, consequently, androgen production, thus reducing the supply of estrogens available to developing follicles.

Effect of Splenectomy on the Activity of Drug-Metabolizing Enzymes in the Liver of Rats

1971 ◽  
Vol 49 (3) ◽  
pp. 161-166 ◽  
Author(s):  
Jules Brodeur ◽  
Claude Marchand
Keyword(s):  
Indirect Evidence ◽  
Female Rats ◽  
Microsomal Enzymes ◽  
Drug Metabolizing Enzyme ◽  
Effect Of Splenectomy ◽  
Maximal Induction ◽  
Metabolizing Enzyme ◽  
Cytochrome P 450 ◽  
Liver Microsomal Enzymes

Splenectomy was performed in adult female rats in order to investigate the influence of removal of the spleen on liver microsomal enzymes and cytochrome P-450 in vitro, as well as on the pharmacological activity of certain drugs in intact animals. Splenectomy significantly decreases the amount of cytochrome P-450 at 1 and 4 days after the operation, but not at 7 days. The activity of the enzymes catalyzing the metabolism of parathion, p-nitroanisole, and zoxazolamine is also decreased 4 days after splenectomy, whereas that of the enzymes involved in the metabolism of hexobarbital is unchanged. The maximal induction by phenobarbital of the enzymatic activities catalyzing the metabolism of parathion, p-nitroanisole, and zoxazolamine is prevented by splenectomy. Splenectomy exerts very little effect on plasma levels of hexobarbital and hexobarbital sleeping time; however, in both control and phenobarbital-pretreated rats, splenectomy results in a marked increase in the duration of zoxazolamine paralysis. These results indicate that splenectomy exerts inhibitory effects on certain liver microsomal enzymes, and provide some indirect evidence in support of the view that the hepatic blood supply is important for maintaining normal levels of drug-metabolizing enzyme activity in the liver.

Aniline and hexobarbital hydroxylases from rat lung and kidney: neither sex dependent nor inducible with phenobarbital

1982 ◽  
Vol 60 (10) ◽  
pp. 1247-1250 ◽  
Author(s):  
Janet L. Lister ◽  
Bruce B. Virgo
Keyword(s):  
Microsomal Protein ◽  
Female Rats ◽  
Rat Lung ◽  
Male And Female ◽  
Aniline Hydroxylase ◽  
Protein Levels ◽  
Male And Female Rats ◽  
Males And Females ◽  
Cytochrome P 450 ◽  
Lung And Kidney

The basal activities of aniline hydroxylase (AH), hexobarbital hydroxylase (HH), and ethylmorphine N-demethylase (ED) were measured in the 9000 × g supernatant of kidneys and lungs from male and female rats. No ED activity was detected in any tissue although all tissues N-demethylated three other substrates. The activities of AH and HH were not sex dependent in either kidney or lung. Similarly, pulmonary and renal microsomal protein concentrations were independent of sex. In addition, cytochrome P-450 levels in the kidney were the same in males and females (pulmonary P-450 was not measured). The pulmonary hydroxylases were more active than the renal enzymes in both sexes. In males, phenobarbital (ip, 50 rng∙kg−1∙day−1 for 3 days) failed to induce AH or HH in either kidney or lung; it did not increase the weight or microsomal protein levels of these organs and it also failed to increase renal P-450. Thus, the basal activities of AH and HH in lungs and kidneys are not different in male and female rats and are not increased by phenobarbital.

AUGMENTATION BY CHLORMADINONE OF THE UTERINE WEIGHT RESPONSE TO HUMAN CHORIONIC GONADOTROPHIN IN INTACT IMMATURE RATS

1965 ◽  
Vol 33 (3) ◽  
pp. 447-454
Author(s):  
M. J. K. HARPER
Keyword(s):  
Single Injection ◽  
Direct Action ◽  
Follicular Development ◽  
Chorionic Gonadotrophin ◽  
Human Chorionic Gonadotrophin ◽  
Female Rats ◽  
Uterine Weight ◽  
Control Value ◽  
Orally Active ◽  
Stimulation Of

SUMMARY Administration of chlormadinone, an orally active progestational agent without significant oestrogenic activity, to intact immature female rats did not affect either ovarian or uterine weight significantly compared with controls. A single injection of human chorionic gonadotrophin (HCG) caused a 73 % increase in uterine weight in 24 hr. over the control value. This dose significantly increased ovarian weight and although it caused some stimulation of follicular development, ovulation during this time did not occur. When animals were treated with chlormadinone for 8 days, and received HCG on the 8th day, uterine weight was 170% greater than in the controls and 56% greater than with HCG alone. The uterine weight produced was similar to that found in animals treated with mestranol, a potent oestrogen, and HCG. In ovariectomized animals HCG did not affect uterine weight, while the small increase produced by chlormadinone was unaltered when HCG also was given. Mechanisms are discussed by which this augmentation of the uterine response to HCG might be produced. It seems most likely that chlormadinone administration causes storage of endogenous gonadotrophin in the pituitary, and that the exogenous gonadotrophin acts as the 'trigger' for the release of stored hormone, probably by a direct action on the hypothalamus.

scholarly journals Pentachloronitrobenzene alters progesterone production and primordial follicle recruitment in cultured granulosa cells and rat ovary†

2019 ◽  
Vol 102 (2) ◽  
pp. 511-520
Author(s):  
Yanrong Kuai ◽  
Xiaobo Gao ◽  
Huixia Yang ◽  
Haiyan Luo ◽  
Yang Xu ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Granulosa Cells ◽  
Crop Production ◽  
Follicular Development ◽  
Mitogen Activated Protein Kinase ◽  
Dependent Manner ◽  
Serum Progesterone ◽  
Primordial Follicles ◽  
Progesterone Production

Abstract Pentachloronitrobenzene (PCNB) is an organochlorine fungicide widely used for crop production and has become an environmental concern. Little is known about the effect of PCNB on ovarian steroidogenesis and follicular development. We found that PCNB stimulated Star expression and progesterone production in cultured rat granulosa cells in a dose-dependent manner. PCNB activated mitogen-activated protein kinase (MAPK3/1) extracellulat regulated kinase (ERK1/2), thus inhibition of either protein kinase A (PKA) or MAPK3/1 signaling pathway significantly attenuated progesterone biosynthesis caused by PCNB, suggesting that PCNB induced progesterone production by activating the cyclic adenosine monophosphate (cAMP/PKA) and MAPK3/1 signaling pathways. Further investigation demonstrated that PCNB induced Star expression and altered MAPK3/1 signaling in ovary tissues of immature SD rats treated with PCNB at the dose of 100, 200, or 300 mg/kg by daily gavage for 7 days, while serum progesterone level was dose-dependently decreased. We demonstrated that PCNB exposure accelerated the recruitment of primordial follicles into the growing follicle pool in ovary tissues, accompanied by increased levels of anti-Mullerian hormone (AMH) in both ovary tissues and serum. Taken together, our data demonstrate for the first time that PCNB stimulated Star expression, altered MAPK3/1 signaling and progesterone production in vivo and in vitro, and accelerated follicular development with a concomitant increase in AMH in ovary tissues and serum. Our findings provide novel insight into the toxicity of PCNB to animal ovary function.

Inhibition of LH-stimulated cyclic AMP formation in pre-ovulatory rat granulosa cells by follicular fluid

1980 ◽  
Vol 95 (1) ◽  
pp. 84-89 ◽  
Author(s):  
Knut Nordenström ◽  
Anita Sjögren ◽  
Lars Hamberger
Keyword(s):  
Granulosa Cells ◽  
Follicular Fluid ◽  
Phosphodiesterase Inhibitor ◽  
Inhibitory Effect ◽  
Female Rats ◽  
Bicarbonate Buffer ◽  
Ovulatory Follicles

Abstract. Immature female rats were injected sc with a single dose of PMSG to induce growth and maturation of ovarian follicles. In the morning of prooestrus the rats were given a single ip injection of LH (10 μg/rat) or 0.154 m NaCl, 2 h prior to sacrifice. Granulosa cells were isolated from the pre-ovulatory follicles and incubated in Krebs bicarbonate buffer, for 1 h with or without in vitro addition of various test substances. Following incubation the amounts of cAMP in tissue plus medium were determined. It was found that the isolated granulosa cells exposed to LH in vivo responded to the addition of LH in vitro with a production of high amounts of cAMP, i.e. these cells were not refractory to LH stimulation and in fact responded better than granulosa cells isolated from ovaries not exposed to LH in vivo. The addition to the incubation medium of follicular fluid (FFl) obtained from pre-ovulatory follicles decreased the effect of LH in vitro when added at a final concentration of 1% and completely abolished it at a concentration of 3%. Removal of steroids from the FFl did not influence the inhibitory effect and the addition of a phosphodiesterase inhibitor (IBMX) in vitro did not alter the results in principle. These results point to the existence of a factor in the FF1 which interacts with the sensitivity of the isolated preovulatory granulosa cells to repeated exposures to LH. Characterization of this factor is subject to further investigations.

255 THE ESTROGENIC EVALUATION OF PARABENS USING RAT UTERINE CALBINDIN-D9k

2010 ◽  
Vol 22 (1) ◽  
pp. 285
Author(s):  
T. T. B. Vo ◽  
E. B. Jeung
Keyword(s):  
Gene Expression ◽  
Adverse Effects ◽  
Treated Group ◽  
Environmental Chemicals ◽  
Female Rats ◽  
Protein Levels ◽  
Calbindin D9k ◽  
The Difference

In the current study, calbindin-D9k (CaBP-9k), a potent biomarker for screening estrogen-like environmental chemicals in vivo and in vitro, was adopted to examine the potential estrogen-like property of the following parabens: propyl-, isopropyl-, butyl-, and isobutyl-paraben. Immature female rats were administered for 3 days from postnatal day 14 to 16 with 17?-ethinylestradiol (EE, 1 mg/kg of body weight (BW) per day) or parabens (62.5, 250, and 1000 mg/kg of BW per day). In uterotrophic assays, significantly increased uterus weights were detected in the EE-treated group and in the groups treated with the greatest dose of isopropyl-, butyl- and isobutyl-paraben. In addition, these parabens induced uterine CaBP-9k mRNA and protein levels, whereas co-treatment of parabens and fulvestrant (Faslodex, formerly known as ICI 182, 780), a pure estrogen receptor (ER) antagonist, completely reversed the paraben-induced gene expression and increased uterine weights. To investigate the ER-mediated mechanism(s) by which parabens exert their effects, the expression level of ERα and progesterone receptor (PR) was analyzed. Exposure to EE or parabens caused a dramatic decrease in expression of both ER? mRNA and protein levels, whereas co-treatment with fulvestrant reversed these effects. These data showed the difference of CaBP-9k and ER? expression, suggesting that CaBP-9k might not express via ER? pathway. In the effect of parabens on CaBP-9k expression through PR mediation, a significantly increased expression of uterine PR gene, a well-known ER regulating gene, at both transcriptional and translational levels was indicated in the greatest dose of isopropyl- and butyl-paraben. These parabens induced PR gene expression that was completely blocked by fulvestrant. This result indicates that CaBP-9k expression might involve PR mediates in the estrogenic effect of paraben in immature rat uteri. Taken together, parabens exhibited an estrogen-like property in vivo, which might be mediated by a PR and/or ER? signaling pathway. In addition, our results expanded the current understanding of the potential adverse effects of parabens associated with their estrogen-like activities. Further investigation is needed to elucidate in greater detail the adverse effects of parabens in humans and wildlife.

scholarly journals Platelet-derived growth factor B restores vascular barrier integrity and diminishes permeability in ovarian hyperstimulation syndrome

2020 ◽  
Vol 26 (8) ◽  
pp. 585-600
Author(s):  
Natalia Pascuali ◽  
Leopoldina Scotti ◽  
Gonzalo Oubiña ◽  
Ignacio de Zúñiga ◽  
Mariana Gomez Peña ◽  
...  
Keyword(s):  
At Risk ◽  
Growth Factor ◽  
Rat Model ◽  
Ovarian Hyperstimulation Syndrome ◽  
Regulatory Protein ◽  
Platelet Derived Growth Factor ◽  
Corpora Lutea ◽  
Ovarian Hyperstimulation ◽  
Serum Progesterone ◽  
Protein Levels

Abstract Although advances in the prediction and management of ovarian hyperstimulation syndrome (OHSS) have been introduced, complete prevention is not yet possible. Previously, we and other authors have shown that vascular endothelial growth factor, angiopoietins (ANGPTs) and sphingosine-1-phosphate are involved in OHSS etiology. In addition, we have demonstrated that ovarian protein levels of platelet-derived growth factor (PDGF) ligands -B and -D decrease in an OHSS rat model, whilst PDGFR-β and ANGPT2 remain unchanged. In the present work, we investigated the role of PDGF-B in OHSS by evaluating ligand protein levels in follicular fluid (FF) from women at risk of developing OHSS and by using an immature rat model of OHSS. We demonstrated that PDGF-B and PDGF-D are lower in FF from women at risk of developing OHSS compared to control patients (P &lt; 0.05). In the OHSS rat model, PDGF-B (0.5 µg/ovary) administration decreased ovarian weight (P &lt; 0.05), reduced serum progesterone (P &lt; 0.05) and lowered the percentage of cysts (P &lt; 0.05), compared to untreated OHSS rats, but had no effect on the proportion of follicles or corpora lutea (CL). PDGF-B treatment also restored the expression of steroidogenic acute regulatory protein (P &lt; 0.05) and P450 cholesterol side-chain cleavage enzyme (P &lt; 0.01) to control levels. In addition, PDGF-B increased the peri-endothelial cell area in CL and cystic structures, and reduced vascular permeability compared to untreated OHSS ovaries. Lastly, PDGF-B increased the levels of junction proteins claudin-5 (P &lt; 0.05), occludin (P &lt; 0.05) and β-catenin (P &lt; 0.05), while boosting the extracellular deposition of collagen IV surrounding the ovarian vasculature (PP &lt; 0.01), compared to OHSS alone. In conclusion, our findings indicate that PDGF-B could be another crucial mediator in the onset and development of OHSS, which may lead to the development of novel prediction markers and therapeutic strategies.

BHLHE40 plays a pathological role in pre-eclampsia through upregulating SNX16 by transcriptional inhibition of miR-196a-5p

2020 ◽  
Vol 26 (7) ◽  
pp. 532-548 ◽  
Author(s):  
Chunmei Mi ◽  
Bin Ye ◽  
Zhou Gao ◽  
Jinzhi Du ◽  
Ruizhen Li ◽  
...  
Keyword(s):  
Cell Migration ◽  
Neonatal Morbidity ◽  
Inhibitory Effect ◽  
Abnormal Development ◽  
Luciferase Reporter ◽  
Protein Levels ◽  
Transcriptional Inhibition ◽  
Uterine Perfusion

Abstract Pre-eclampsia (PE), which results from abnormal placentation, is a primary cause of maternal and neonatal morbidity and mortality. However, the causes of abnormal development of the placenta remain poorly understood. BHLHE40 is a transcriptional repressor in response to hypoxia. Bioinformatics analysis demonstrated that BHLHE40 negatively regulates miR-196a-5p expression, which may decrease miR-196a-5p to target SNX16. Since SNX16 exerts an inhibitory effect on cell migration, it may disrupt trophoblast cell migration in placentation. Therefore, the objective of this study was to explore a possible role of the BHLHE40/miR-196a-5p/SNX16 axis in PE pathogenesis. BHLHE40, miR-196a-5p and SNX16 mRNA and/or protein levels were detected in PE and normal placenta tissues. PE models in vitro and in vivo were constructed by culturing trophoblasts under hypoxia and reducing the uterine perfusion pressure in pregnant C57/BL6N mice, respectively. BHLHE40 and SNX16 were upregulated in PE placenta, while miR-196a-5p was downregulated. Knockdown of BHLHE40 reversed miR-196a-5p expression in trophoblasts under hypoxia, and upregulation of miR-196a-5p inhibited SNX16 expression. As indicated by ChIP assay, BHLHE40 bound to the promoter of the miR-196a-5p gene; luciferase reporter analysis showed that miR-196a-5p could bind to the 3ʹ-untranslated region of SNX16 mRNA. Knockdown of either BHLHE40 or SNX16, or an increase in miR-196a-5p, restored cell viability, migration, invasion and matrix metalloprotein (MMP)-2 and MMP-9 expression under hypoxia. BHLHE40 knockdown also alleviated PE symptoms in pregnant C57/BL6N mice. This study supports involvement of the BHLHE40/miR-196a-5p/SNX16 axis in PE pathogenesis; Proper adjustment of the BHLHE40/miR-196a-5p/SNX16 axis is able to attenuate PE symptoms.

A novel mechanism of olanzapine-induced lipid accumulation

2011 ◽  
Vol 26 (S2) ◽  
pp. 906-906 ◽  
Author(s):  
S. Dzitoyeva ◽  
H. Chen ◽  
R. Manev ◽  
H. Manev
Keyword(s):  
Lipid Content ◽  
Direct Action ◽  
Inhibitory Effect ◽  
Experimental Conditions ◽  
Cell Content ◽  
Metabolic Alterations ◽  
Low Concentrations ◽  
Mrna Content ◽  
Quantitative Western Blot

IntroductionSecond generation antipsychotic drugs (SGADs) including olanzapine trigger adverse metabolic alterations possibly by a direct action on adipocytes.Objectives and aimsThe system of the inflammatory 5-lipoxygenase (5-LOX) and its activating protein (FLAP) have been implicated in lipid dysfunction in obesity. We investigated whether this system could participate in the adipogenic action of olanzapine.MethodsExperiments were performed in 3T3-L1 adipocytes in vitro. Cells were treated with olanzapine and a FLAP inhibitor MK-886. Their lipid content, 5-LOX and FLAP mRNA content, and FLAP protein content were measured.ResultsOlanzapine treatment did not affect the cell content of 5-LOX mRNA; however, it decreased FLAP mRNA content at day five but not 24 hours after olanzapine addition. The inhibitory effect of olanzapine on FLAP expression was confirmed by quantitative Western blot assays. In the absence of a FLAP inhibitor, low concentrations of olanzapine (0.5 and 5 μM) increased lipid content only by about 13% (compared to about a 56% increase induced by 50 μM olanzapine) whereas in the presence of MK-886 these concentrations of olanzapine produced lipid increases comparable to the increase caused by 50 μM. In these experimental conditions, MK-886 alone did not alter the cell content of lipids.Conclusions5-LOX system may be involved in lipid dysfunction not only in conditions of obesity but possibly in SGAD-related metabolic alterations. The known polymorphism in the genes of the human 5-LOX system could play a role in setting a variable individual susceptibility to the metabolic side effects of SGADs.

scholarly journals Inhibitory effect of leptin on the rat ovary during the ovulatory process

Reproduction ◽  
2006 ◽  
Vol 132 (5) ◽  
pp. 771-780 ◽  
Author(s):  
A G Ricci ◽  
M P Di Yorio ◽  
A G Faletti
Keyword(s):  
Leptin Receptor ◽  
Inhibitory Effect ◽  
Chorionic Gonadotrophin ◽  
Prostaglandin E ◽  
Negative Effects ◽  
Serum Progesterone ◽  
Leptin Receptors ◽  
The Media ◽  
Ovulatory Process

The aims of this study were to investigate the negative action of leptin on some intraovarian ovulatory mediators during the ovulatory process and to assess whether leptin is able to alter the expression of its ovarian receptors. Immature rats primed with gonadotrophins were used to induce ovulation. Serum leptin concentration was diminished 4 h after human chorionic gonadotrophin (hCG) administration, whereas the ovarian expression of leptin receptors, measured by western blot, was increased by the gonadotrophin treatment. Serum progesterone level, ovulation rate and ovarian prostaglandin E (PGE) content were reduced in rats primed with equine chorionic gonadotrophin (eCG)/hCG and treated with acute doses of leptin (five doses of 5 μg each). These inhibitory effects were confirmed by in vitro studies, where the presence of leptin reduced the concentrations of progesterone, PGE and nitrites in the media of both ovarian explants and preovulatory follicle cultures. We also investigated whether these negative effects were mediated by changes in the expression of the ovarian leptin receptors. Since leptin treatment did not alter the expression of ovarian leptin receptor, the inhibitory effect of leptin on the ovulatory process may not be mediated by changes in the expression of its receptors at ovarian level, at least at the concentrations assayed. In summary, the ovulatory process was significantly inhibited in response to an acute treatment with leptin, and this effect may be due, at least in part, to the direct or indirect impairment of some ovarian factors, such as prostaglandins and nitric oxide.

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