Cholesterol transport and steroidogenesis by the corpus luteum

The synthesis of progesterone by the corpus luteum is essential for the establishment and maintenance of early pregnancy. Regulation of luteal steroidogenesis can be broken down into three major events; luteinization (i.e., conversion of an ovulatory follicle), luteal regression, and pregnancy induced luteal maintenance/rescue. While the factors that control these events and dictate the final steroid end products are widely varied among different species, the composition of the corpus luteum (luteinized thecal and granulosa cells) and the enzymes and proteins involved in the steroidogenic pathway are relatively similar among all species. The key factors involved in luteal steroidogenesis and several new exciting observations regarding regulation of luteal steroidogenic function are discussed in this review

Co-release of noradrenaline and dopamine in the cerebral cortex elicited by single train and repeated train stimulation of the locus coeruleus

BACKGROUND: Previous studies by our group suggest that extracellular dopamine (DA) and noradrenaline (NA) may be co-released from noradrenergic nerve terminals in the cerebral cortex. We recently demonstrated that the concomitant release of DA and NA could be elicited in the cerebral cortex by electrical stimulation of the locus coeruleus (LC). This study analyses the effect of both single train and repeated electrical stimulation of LC on NA and DA release in the medial prefrontal cortex (mPFC), occipital cortex (Occ), and caudate nucleus. To rule out possible stressful effects of electrical stimulation, experiments were performed on chloral hydrate anaesthetised rats. RESULTS: Twenty min electrical stimulation of the LC, with burst type pattern of pulses, increased NA and DA both in the mPFC and in the Occ. NA in both cortices and DA in the mPFC returned to baseline within 20 min after the end of the stimulation period, while DA in the Occ reached a maximum increase during 20 min post-stimulation and remained higher than baseline values at 220 min post-stimulation. Local perfusion with tetrodotoxin (TTX, 10 μM) markedly reduced baseline NA and DA in the mPFC and Occ and totally suppressed the effect of electrical stimulation in both areas. A sequence of five 20 min stimulations at 20 min intervals were delivered to the LC. Each stimulus increased NA to the same extent and duration as the first stimulus, whereas DA remained elevated at the time next stimulus was delivered, so that baseline DA progressively increased in the mPFC and Occ to reach about 130 and 200% the initial level, respectively. In the presence of the NA transport (NAT) blocker desipramine (DMI, 100 μM), multiple LC stimulation still increased extracellular NA and DA levels. Electrical stimulation of the LC increased NA levels in the homolateral caudate nucleus, but failed to modify DA level. CONCLUSION: The results confirm and extend that LC stimulation induces a concomitant release of DA and NA in the mPFC and Occ. The different time-course of LC-induced elevation of DA and NA suggests that their co-release may be differentially controlled

Bioinformatic detection of E47, E2F1 and SREBP1 transcription factors as potential regulators of genes associated to acquisition of endometrial receptivity

<p>Abstract</p> <p>Background</p> <p>The endometrium is a dynamic tissue whose changes are driven by the ovarian steroidal hormones. Its main function is to provide an adequate substrate for embryo implantation. Using microarray technology, several reports have provided the gene expression patterns of human endometrial tissue during the window of implantation. However it is required that biological connections be made across these genomic datasets to take full advantage of them. The objective of this work was to perform a research synthesis of available gene expression profiles related to acquisition of endometrial receptivity for embryo implantation, in order to gain insights into its molecular basis and regulation.</p> <p>Methods</p> <p>Gene expression datasets were intersected to determine a consensus endometrial receptivity transcript list (CERTL). For this cluster of genes we determined their functional annotations using available web-based databases. In addition, promoter sequences were analyzed to identify putative transcription factor binding sites using bioinformatics tools and determined over-represented features.</p> <p>Results</p> <p>We found 40 up- and 21 down-regulated transcripts in the CERTL. Those more consistently increased were C4BPA, SPP1, APOD, CD55, CFD, CLDN4, DKK1, ID4, IL15 and MAP3K5 whereas the more consistently decreased were OLFM1, CCNB1, CRABP2, EDN3, FGFR1, MSX1 and MSX2. Functional annotation of CERTL showed it was enriched with transcripts related to the immune response, complement activation and cell cycle regulation. Promoter sequence analysis of genes revealed that DNA binding sites for E47, E2F1 and SREBP1 transcription factors were the most consistently over-represented and in both up- and down-regulated genes during the window of implantation.</p> <p>Conclusions</p> <p>Our research synthesis allowed organizing and mining high throughput data to explore endometrial receptivity and focus future research efforts on specific genes and pathways. The discovery of possible new transcription factors orchestrating the CERTL opens new alternatives for understanding gene expression regulation in uterine function.</p

Combined α2- and D2-receptor blockade activates noradrenergic and dopaminergic neurons, but extracellular dopamine in the prefrontal cortex is determined by uptake and release from noradrenergic terminals

Experimental and clinical evidence indicates a deficit of release and function of dopamine in schizophrenia and suggests that a(2)-adrenoceptor antagonists rescue dopamine deficit and improve the antipsychotic efficacy of D-2-receptor antagonists. In anesthetized male rats, we investigated how the blockade of a(2)- and D-2-receptors by atipamezole and raclopride, respectively, modified the firing of noradrenergic neurons in the locus coeruleus (LC) and dopaminergic neurons in the ventral tegmental area (VTA). In freely moving rats, we studied how atipamezole and raclopride modified extracellular noradrenaline, dopamine, and DOPAC levels in the medial prefrontal cortex (mPFC) through microdialysis. When administered alone, atipamezole activated LC noradrenaline but not VTA dopamine cell firing. Combined with raclopride, atipamezole activated dopamine cell firing above the level produced by raclopride. Atipamezole increased extracellular dopamine to the same level, whether administered alone or combined with raclopride. In the presence of the noradrenaline transporter (NET) inhibitor, atipamezole combined with raclopride increased extracellular dopamine beyond the level produced by either compound administered alone. The results suggest that a) the D-2-autoreceptor blockade is required for LC noradrenaline to activate VTA cell firing; b) the level of dopamine released from dopaminergic terminals is determined by NET; c) the elevation of extracellular dopamine levels in the mPFC is the resultant of dopamine uptake and release from noradrenergic terminals, independent of dopaminergic cell firing and release; and d) LC noradrenergic neurons are an important target for treatments to improve the prefrontal deficit of dopamine in neuropsychiatric pathologies

Glucotransporters expression and function in the human endometrium from normal and polycystic ovary syndrome women: Effect of metformin treatment

Con el objetivo de evaluar la expresión y función de GLUT1 y GLUT4 en el endometrio de: mujeres control (C) en diferentes fases del ciclo menstrual, SOP con insulinorresistencia (IR) o sin ella y SOP-IR tratadas con metformina (M), se obtuvo endometrio de mujeres con fertilidad comprobada que se sometieron a salpingoligadura (C), mujeres SOP anovulatorias con IR o sin ella y SOP-IR que recibieron 1700 mg/día de M durante 2 años. Se evaluó la expresión de GLUT por qRT-PCR e inmunohistoquímica. Se estudió el transporte de glucosa por incorporación de 2-desoxi-[ 3 H]-glucosa (2-DG) en condiciones basales y bajo estímulo de insulina (100 ng/ ml). En endometrio secretor C, la expresión de GLUT1 aumentó y la de GLUT4 disminuyó comparado con el grupo proliferativo (p<0,01 y p<0,05). Los niveles de GLUT4 y el transporte basal de 2-DG se encontró reducido en SOP-IR (p<0,05). La insulina aumentó la captación basal de 2-DG en los endometrios proliferativos C (p<0,02), SOP-nIR (p<0,05) y SOP-IRM (p<0,001), y fue incapaz de estimular la incorporación de glucosa en el endometrio SOP-IR y secretor C. Estos resultados indican que existe una dinámica fisiológica en la expresión de los GLUT en el endometrio control. El GLUT1 fue preponderante en la fase secretora. El endometrio de mujeres SOP-IR es resistente a la acción de la insulina. Esta resistencia estaría asociada a la disminución en la expresión de GLUT4. La metformina es capaz de incrementar la expresión de este transportador, recuperando la capacidad moduladora de insulina sobre la captación de glucosa en el endometrio de pacientes SOP-IR.In order to evaluate the expression and function of GLUT1 and GLUT4 in the endometrium: women in different phases of the menstrual cycle, PCOS with or without insulin resistance (IR) and PCOS-IR treated with metformin (IRM). Endometrium was obtained from fertile women underwent tubal sterilization (C), anovulatory PCOS women with or without IR and PCOS-IR who received 1700 mg daily of M for two years. GLUTs expression was evaluated by qRT-PCR and immunohistochemistry. Glucose uptake was assessed by incorporation of 2-desoxy-[ 3 H]-glucose (2-DG) in both basal condition and under insulin stimulation (100 ng/ml). In C secretory endometrium GLUT1 expression was increased and GLUT4 was decreased compared with proliferative group (p<0.01 and p<0.05). GLUT4 level and basal 2-DG uptake were reduced in PCO-IR (p<0.05). Insulin increased basal 2-DG uptake in C proliferative endometrium (p<0.02), PCOS nIR (p<0.05) and PCOSIRM (p<0.001), being unable to stimulate glucose incorporation in both PCOS-IR and C secretory endometrium. These results suggest a physiological dynamics of GLUTs expression in normal endometrium. GLUT1 is the predominant form in secretory phase. Endometrium of women with PCOS-IR displayed insulin resistance. The decreased expression of GLUT4 is a feature of IR at the endometrial level. Metformin increases the expression of this transporter, recovering the function of insulin on glucose uptake in PCOS-IR endometrium.Fil: Pustovrh, María Carolina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Fisiología, Biología Molecular y Neurociencias. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Fisiología, Biología Molecular y Neurociencias; ArgentinaFil: Villarroel, Claudio. Universidad de Santiago de Chile. Hospital Clinico San Borja Arriaran. Instituto de Investigaciones Materno Infantil; ChileFil: Arriagada, Claudia. Universidad de Santiago de Chile. Hospital Clinico San Borja Arriaran. Instituto de Investigaciones Materno Infantil; ChileFil: Muñoz, Alex. Universidad de Santiago de Chile. Hospital Clinico San Borja Arriaran. Instituto de Investigaciones Materno Infantil; ChileFil: Kohen, Paulina. Universidad de Santiago de Chile. Hospital Clinico San Borja Arriaran. Instituto de Investigaciones Materno Infantil; ChileFil: Devoto, Luigi. Universidad de Santiago de Chile. Hospital Clinico San Borja Arriaran. Instituto de Investigaciones Materno Infantil; Chil

Noradrenergic Source of Dopamine Assessed by Microdialysis in the Medial Prefrontal Cortex

Previous results indicate that dopamine (DA) release in the medial prefrontal cortex (mPFC) is modified by α2 adrenoceptor- but not D2 DA receptor- agonists and antagonists, suggesting that DA measured by microdialysis in the mPFC originates from noradrenergic terminals. Accordingly, noradrenergic denervation was found to prevent α2-receptor-mediated rise and fall of extracellular DA induced by atipamezole and clonidine, respectively, in the mPFC. The present study was aimed to determine whether DA released by dopaminergic terminals in the mPFC is not detected by in vivo microdialysis because is readily taken up by norepinephrine transporter (NET). Accordingly, the D2-antagonist raclopride increased the electrical activity of DA neurons in the ventral tegmental area (VTA) and enhanced extracellular DOPAC but failed to modify DA in the mPFC. However, in rats whose NET was either inactivated by nisoxetine or eliminated by noradrenergic denervation, raclopride still elevated extracellular DOPAC and activated dopaminergic activity, but also increased DA. Conversely, the D2-receptor agonist quinpirole reduced DOPAC but failed to modify DA in the mPFC in control rats. However, in rats whose NET was eliminated by noradrenergic denervation or inhibited by locally perfused nisoxetine, quinpirole maintained its ability to reduce DOPAC but acquired that of reducing DA. Moreover, raclopride and quinpirole, when locally perfused into the mPFC of rats subjected to noradrenergic denervation, were able to increase and decrease, respectively, extracellular DA levels, while being ineffective in control rats. Transient inactivation of noradrenergic neurons by clonidine infusion into the locus coeruleus, a condition where NET is preserved, was found to reduce extracellular NE and DA in the mPFC, whereas noradrenergic denervation, a condition where NET is eliminated, almost totally depleted extracellular NE but increased DA. Both transient inactivation and denervation of noradrenergic neurons were found to reduce the number of spontaneously active DA neurons and their bursting activity in the VTA. The results indicate that DA released in the mPFC by dopaminergic terminals is not detected by microdialysis unless DA clearance from extracellular space is inactivated. They support the hypothesis that noradrenergic terminals are the main source of DA measured by microdialysis in the mPFC during physiologically relevant activities

Combined α2- and D2-receptor blockade activates noradrenergic and dopaminergic neurons, but extracellular dopamine in the prefrontal cortex is determined by uptake and release from noradrenergic terminals

Experimental and clinical evidence indicates a deficit of release and function of dopamine in schizophrenia and suggests that α2-adrenoceptor antagonists rescue dopamine deficit and improve the antipsychotic efficacy of D2-receptor antagonists. In anesthetized male rats, we investigated how the blockade of α2- and D2-receptors by atipamezole and raclopride, respectively, modified the firing of noradrenergic neurons in the locus coeruleus (LC) and dopaminergic neurons in the ventral tegmental area (VTA). In freely moving rats, we studied how atipamezole and raclopride modified extracellular noradrenaline, dopamine, and DOPAC levels in the medial prefrontal cortex (mPFC) through microdialysis. When administered alone, atipamezole activated LC noradrenaline but not VTA dopamine cell firing. Combined with raclopride, atipamezole activated dopamine cell firing above the level produced by raclopride. Atipamezole increased extracellular dopamine to the same level, whether administered alone or combined with raclopride. In the presence of the noradrenaline transporter (NET) inhibitor, atipamezole combined with raclopride increased extracellular dopamine beyond the level produced by either compound administered alone. The results suggest that a) the D2-autoreceptor blockade is required for LC noradrenaline to activate VTA cell firing; b) the level of dopamine released from dopaminergic terminals is determined by NET; c) the elevation of extracellular dopamine levels in the mPFC is the resultant of dopamine uptake and release from noradrenergic terminals, independent of dopaminergic cell firing and release; and d) LC noradrenergic neurons are an important target for treatments to improve the prefrontal deficit of dopamine in neuropsychiatric pathologies

Estrogen Metabolites in Human Corpus Luteum Physiology: Differential Effects on Angiogenic Activity

OBJECTIVE: To determine tissue concentrations of E2, estrone, P, and estrogens metabolites (EMs) 2-methoxyestradiol, 2-methoxyestrone, 4-hydroxyestrone, and 16-ketoestradiol in corpus luteum (CL) of different ages, and after hCG administration; and to examine the effects of EMs on vascular endothelial growth factor (VEGF) secretion and angiogenic activity released by cultured luteinizing granulosa cells in the presence and absence of hCG. DESIGN: Experimental study. SETTING: University. PATIENT(S): Thirty-two healthy women of reproductive age. INTERVENTION(S): Corpus luteum was collected at the time of minilaparotomy for tubal sterilization, at varying stages of the luteal phase (LP). Late-LP CL was collected 24 hours after IM administration of 10,000 IU hCG. Granulosa cells were isolated from follicular aspirates obtained from healthy women participating in our IVF program for male factor infertility. MAIN OUTCOMES MEASURE(S): Estrogen metabolite concentrations were determined in CL tissue, and VEGF was assessed in conditioned medium. The angiogenic activity was analyzed by bioassay. RESULT(S): Concentrations of EMs with proangiogenic activity (16-ketoestradiol and 4-hydroxyestrone) were higher in early and mid-LP CL vs. late-LP CL. These EMs and hCG increased VEGF production and angiogenic activity. Conversely, late-LP CL had significantly higher levels of 2-methoxyestrone and 2-methoxyestradiol, which have antiangiogenic activity. Administration of hCG reduced the production of these EMs. CONCLUSION(S): Our findings suggest that the EMs are important paracrine modulators of CL function. Administration of hCG increases the production of EMs with proangiogenic activity and reduces the secretion of those EMs with antiangiogenic action, suggesting a novel mechanism by which the late-LP CL is rescued in conception cycles

Epidemiological study of pathogens isolated from blood in Liguria during 2011

Objectives. An epidemiological study addressed to identify the most represented pathogens isolated from blood and to evaluate their antibiotic susceptibility patterns, was conducted. Methods. Five clinical microbiology laboratories, homogenously distributed in Liguria, were required to collected all consecutive non-duplicates strains isolated from blood cultures during March 2011 to May 2011. the strains were sent to the reference laboratory (Section of Microbiology, DISC, University of Genoa, Italy). Results. A total of 159 microorganisms were enrolled, including 81 Gram positive, 69 Gram negative and 9 fungi.The most represented pathogens were: Escherichia coli (35), Staphylococcus aureus (26), S. epidermidis (20), S. hominis (10). Samples were collected mainly from medicine (59 isolates).Among the staphylococci, the most active molecules were: vancomycin (100% of susceptible strains), teicoplanin (93.4%), trimethoprim-sulfamethoxazole (83.8%) and tobramycin (61.6%). Enterococci showed rates of resistance to vancomycin of 25%. Enterobacteriaceae exhibited resistance to ampicillin (76.9%), ceftriaxone (44.4%), ciprofloxacin (43.3%), trimethoprim-sulfamethoxazole (36.6%) and ceftazidime (32.2%). Conclusions. The data show a higher incidence of Gram positive (51%) in comparison to Gram negative (43.4%). Gram-positive strains showed a high resistance level to fluoroquinolones (92.3%) while Gram-negative resulted resistant to ceftriaxone (44.4%) and fluoroquinolone (43.3%)

Epidemiological study of pathogens isolated from blood in Liguria (January-April 2010)

Objectives. An epidemiological study to identify the most represented pathogens isolated from blood and to evaluate their antibiotic susceptibility patterns, was conducted. Methods. Seven clinical microbiology laboratories, homogeneously distributed in the Ligurian area,were required to collected all consecutive non-duplicates strains isolated froom blood cultures during January 2010 to April 2010. The strains were sent to the reference laboratory (Sezione di Microbiologia del DISC, University of Genoa, Italy). Results. A total of 277 microorganisms were enrolled, including 155 Gram positive and 122 Gram negative.The most represented pathogens were: Escherichia coli (68), Staphylococcus aureus (57), Staphylococcus epidermidis (32), Staphylococcus hominis (17), Pseudomonas aeruginosa (15), Klebsiella pneumoniae (15), Enterococcus faecalis (11). Samples were collected mainly from medicine (66, 33.3%, of this number was determined by E. coli), intensive care units (33, 18.2% of this number consisted of S. epidermidis), surgery (24, 33.3% consisted of E. coli) and infectious diseases (20, of which S. aureus, E. coli and S. epidermidis equally represented 20.0%).Among the Staphylococci the most active molecules were: vancomycin and teicoplanin (100% of susceptible strains), chloramphenicol (92.3%) and trimethoprim-sulfamethoxazole (89.8%). Among the OXA-R Staphylococci (81/123, 65.9%) the most active molecules were: vancomycin and teicoplanin (100% of susceptible strains), chloramphenicol (93.8%) and trimethoprim-sulfamethoxazole (84.8%). Enterococci showed rates of resistance to vancomycin of 5.9%. Enterobacteriaceae exhibited resistance to ampicillin (77.5%), trimethoprim-sulfamethoxazole (42.6%), ciprofloxacin (41.2%), ceftriaxone (37.5%), ceftazidime (28.2%), cefepime (26.7%), cefoxitin (22.1%), piperacillintazobactam (20.4%), imipenem (4.7%) and amikacin (2.9%). The Gram negative non-Enterobacteriaceae showed rates of resistance of 100% to ceftriaxone, 81.3% to trimethoprim-sulfamethoxazole, 42.1% to ciprofloxacin and piperacillin-tazobactam, 33.3% to ceftazidime, 31.6% to cefepime, 27.8% to imipenem, 26.3 % to amikacin. Conclusions. The data show a higher incidence of Gram positive (56%) in comparison to Gram negative (44%).This confirms the high incidence of oxacillino-resistance in Staphylococci in our geographic area.Against Enterobacteriaceae rates of resistance were observed in excess of 20% for all drugs tested except imipenem (4.7%) and amikacin (2.9%). The proportion of imipenem-resistant isolates was constituted of strains of K. pneumoniae carbapenemase producers