Skip to main content

Laszlo Frenyo

Followers

24

Following

19

Co-authors

9

Public Views

Наталья Елизарова

Joanna Niedbalska-Tarnowska

University of Wroclaw

Université de Paris

Vincent Avecilla

arlett sanchez ramos

Sofie Christiansen

Interests

Uploads

Papers by Laszlo Frenyo

Comparison of Individual and Combined Effects of Four Endocrine Disruptors on Estrogen Receptor Beta Transcription in Cerebellar Cell Culture: The Modulatory Role of Estradiol and Triiodo-Thyronine

International Journal of Environmental Research and Public Health, Jun 22, 2016

Background: Humans and animals are continuously exposed to a number of environmental substances t... more Background: Humans and animals are continuously exposed to a number of environmental substances that act as endocrine disruptors (EDs). While a growing body of evidence is available to prove their adverse health effects, very little is known about the consequences of simultaneous exposure to a combination of such chemicals; Methods: Here, we used an in vitro model to demonstrate how exposure to bisphenol A, zearalenone, arsenic, and 4-methylbenzylidene camphor, alone or in combination, affect estrogen receptor β (ERβ) mRNA expression in primary cerebellar cell cultures. Additionally, we also show the modulatory role of intrinsic biological factors, such as estradiol (E2), triiodo-thyronine (T3), and glial cells, as potential effect modulators; Results: Results show a wide diversity in ED effects on ERβ mRNA expression, and that the magnitude of these ED effects highly depends on the presence or absence of E2, T3, and glial cells; Conclusion: The observed potency of the EDs to influence ERβ mRNA expression, and the modulatory role of E2, T3, and the glia suggests that environmental ED effects may be masked as long as the hormonal milieu is physiological, but may tend to turn additive or superadditive in case of hormone deficiency.

Effect of environmental temperature on pigs infected with Pasteurella multocida type A

PubMed, 1987

Percentage of animals with hypothalamic asymmetry in state 3 mitochondrial respiration rate (<i>mrr</i>)

<p>E2 treatment, regardless of satiety states, caused significantly higher proportion of si... more <p>E2 treatment, regardless of satiety states, caused significantly higher proportion of sided animals (Fisher’s exact test, *: p<0.05). In absence of E2, 24 hours food restriction further reduced the extent of hypothalamic asymmetry. Experimental groups: E2+<i>ad lib</i>: estrogen treated, <i>ad libitum</i> fed animals (n = 5); E2+fasted: estrogen treated, fasted animals (n = 6); S+<i>ad lib</i>: vehicle injected, <i>ad libitum</i> fed animals (n = 5); S+fasted: vehicle injected, fasted animals (n = 4). Sidedness was considered if the difference between the left and right hypothalamic sides of the individual was 20% or higher.</p

RESEARCH ARTICLE Estrogen- and Satiety State-Dependent Metabolic Lateralization in the Hypothalamus of Female Rats

Hypothalamus is the highest center and the main crossroad of numerous homeostatic regu-latory pat... more Hypothalamus is the highest center and the main crossroad of numerous homeostatic regu-latory pathways including reproduction and energy metabolism. Previous reports indicate that some of these functions may be driven by the synchronized but distinct functioning of the left and right hypothalamic sides. However, the nature of interplay between the hemi-spheres with regard to distinct hypothalamic functions is still unclear. Here we investigated the metabolic asymmetry between the left and right hypothalamic sides of ovariectomized female rats by measuring mitochondrial respiration rates, a parameter that reflects the inten-sity of cell and tissue metabolism. Ovariectomized (saline injected) and ovariectomized +estrogen injected animals were fed ad libitum or fasted to determine 1) the contribution of estrogen to metabolic asymmetry of hypothalamus; and 2) whether the hypothalamic asym-metry is modulated by the satiety state. Results show that estrogen-priming significantly increased...

$Research paper thumbnail of Preparation of purified perikaryal and synaptosomal mitochondrial fractions from relatively small hypothalamic brain samples$

Preparation of purified perikaryal and synaptosomal mitochondrial fractions from relatively small hypothalamic brain samples

MethodsX, 2016

In order to measure the activity of neuronal mitochondria, a representative proof of neuronal pro... more In order to measure the activity of neuronal mitochondria, a representative proof of neuronal processes, physiologically relevant mitochondrial samples need to be gained as simply as possible. Existing methods are, however, either for tissue samples of large size and/or homogenous microstructures only, or are not tested for mitochondrial function measurements. In the present article we describe a gradient fractionation method to isolate viable and well-coupled mitochondria from relatively heterogeneous histological microstructures such as the hypothalamus. With this new method, we are able to isolate a sufficient amount of functional mitochondria for determination of respiratory activity, in a short period of time, using affordable equipment. Verified by electron microscopy, our method separates highly enriched and well-preserved perikaryal and

Morpho-functional analysis of ecto-nucleoside triphosphate diphosphohydrolases in hypothalamic neurons

Frontiers in Systems Neuroscience, 2009

ABSTRACT The recently discovered ecto-nucleoside triphosphate diphosphohydrolases (NTPDases) are ... more ABSTRACT The recently discovered ecto-nucleoside triphosphate diphosphohydrolases (NTPDases) are mostly transmembrane proteins hydrolyzing ATP and producing substrates for the different purinergic receptors. The NTPDase family consists of 8 isoenzymes. In the central nervous system NTPDase1-3 isoenzymes were detected. In our earlier experiments, we mapped the tissue distribution of NTPDase3 in the central nervous system. NTPDase3 immunoreactivity (IR) was detected exclusively in neurons. Further immunohistochemical and electronmicroscopic studies in the ventrobasal hypothalamic area revealed that NTPDase3 is exclusively associated with excitatory neurons; either as a transmembrane protein or as a protein associated with subcellular organella (e.g. associated with ribosomes, in the matrix of certain mitochondria). Our goal was the further functional characterization of hypothalamic NTPDases. 1) With respect to the estrogen sensitivity of the ventrobasal hypothalamus and to its neuroendocrine role in reproductive processes, we examined whether the expression of NTPDase3 is estrogen dependent. 2) As NTPDase3 IR mitochondria were abundant in the hypothalamic excitatory axon terminals, we tested whether mitochondrial respiration in the hypothalamic synaptosoma can be influenced by applying an NTPDase blocking agent. We show that 1) the hypothalamic expression of NTPDase3 is considerably influenced by the actual estrogen level; 2) NTPDase blocking significantly decreases type 3 mitochondrial respiration and the total mitochondrial respiratory capacity. In conclusion, our results indicate that estrogen regulates the mitochondrial expression of NTPDases and therefore influences the mitochondrial energy (ATP) supply necessary for excitatory neurotransmission in the ventrobasal hypothalamus.

Comparison of individual and combined effects of procainamide and amiodarone in patients with sustained ventricular tachyarrhythmias

Circulation, 1988

To compare the individual and combined electrophysiological effects of amiodarone and procainamid... more To compare the individual and combined electrophysiological effects of amiodarone and procainamide, 35 patients with sustained ventricular arrhythmias underwent programmed stimulation in the control state, after procainamide (mean concentration, 8.7 +/- 2.8 micrograms/ml), after 13 +/- 2 days of amiodarone (1,400 mg/day x 7 days, then 400 mg/day), and after amiodarone with procainamide (mean procainamide concentration, 7.8 +/- 2.2 micrograms/ml). Sustained ventricular tachycardia (VT) was inducible in all 35 patients during treatment with procainamide alone and with amiodarone alone. Procainamide and amiodarone similarly increased the VT cycle length (+68 vs. +61 msec), the corrected QT interval (+63 vs. +49 msec), and the ventricular effective refractory period measured at paced cycle lengths of 600-550 msec (+23 vs. +21 msec) and 400 msec (+25 vs. +23 msec). Procainamide had a more pronounced effect on QRS duration than amiodarone during sinus rhythm (+18 vs. +8 msec, p less than ...

Oestrogens in the mammalian brain: From conception to adulthood — A review

Acta Veterinaria Hungarica, 2007

Environmental and plant oestrogens have been identified as compounds that when ingested, disrupt ... more Environmental and plant oestrogens have been identified as compounds that when ingested, disrupt the physiological pathways of endogenous oestrogen actions and thus, act as agonists or antagonists of oestrogen. Although the risks of exposure to exogenous oestrogens (ExEs) are subject to scientific debate, the question of how ExE exposure affects the central nervous system remains to be answered. We attempt to summarise the mechanisms of oestrogenic effects in the central nervous tissue with the purpose to highlight the avenues potentially used by ExEs. The genomic and rapid, non-genomic cellular pathways activated by oestrogen are listed and discussed together with the best known interneuronal mechanisms of oestrogenic effects. Because the effects of oestrogen on the brain seem to be age dependent, we also found it necessary to put the age-dependent oestrogenic effects in parallel to their intra-and intercellular mechanisms of action. Finally, considering the practical risks of human ExE exposure, we briefly discuss the human significance of this matter. We believe this short review of the topic became necessary because recent data suggest new fields and pathways for endogenous oestrogen actions and have generated the concern that the hidden exposure of humans and domestic animal species to ExEs may also exert its beneficial and/or adverse effects through these avenues.

Glycogenic induction of thyroid hormone conversion and leptin system activation in the liver of postpartum dairy cows

Acta Veterinaria Hungarica, 2009

In the regulation of energy metabolism, the liver plays an important role in the reinforcement of... more In the regulation of energy metabolism, the liver plays an important role in the reinforcement of energy production. In periparturient cows the energy homeostasis turns into a negative energy balance that may shift the physiological regulation of energy balance towards pathological processes. Propylene glycol (PG), as a complementary source of energy used in the nutrition of dairy cows, alters systemic thyroid hormone economy; however, the exact mechanism through which highly glycogenic feed supplements impact liver metabolism is little known. Previous studies showed that only leptin receptors are expressed in the liver of cows, and now we report that leptin mRNA is expressed in the liver of cows as well. The present results show that the mRNA of leptin and its receptors are differentially modulated by the increased energy content of the feed consumed. Simultaneous changes in hepatic type I deiodinase activity suggest that hepatic modulation of the leptin system by PG supplementatio...

BioMed Central Hypothesis NTPDases in the neuroendocrine hypothalamus: Possible energy

regulators of the positive gonadotrophin feedback

NTPDases in the neuroendocrine hypothalamus: Possible energy regulators of the positive gonadotrophin feedback

Reproductive Biology and Endocrinology, 2009

Background: Brain-derived ectonucleoside triphosphate diphosphohydrolases (NTPDases) have been kn... more Background: Brain-derived ectonucleoside triphosphate diphosphohydrolases (NTPDases) have been known as plasma membrane-incorporated enzymes with their ATP-hydrolyzing domain outside of the cell. As such, these enzymes are thought to regulate purinergic intercellular signaling by hydrolyzing ATP to ADP-AMP, thus regulating the availability of specific ligands for various P2X and P2Y purinergic receptors. The role of NTPDases in the central nervous system is little understood. The two major reasons are the insufficient knowledge of the precise localization of these enzymes in neural structures, and the lack of specific inhibitors for the various NTPDases. To fill these gaps, we recently studied the presence of neuron-specific NTPDase3 in the mitochondria of hypothalamic excitatory neurons by morphological and functional methods. Results from those studies suggested that intramitochondrial regulation of ATP levels may play a permissive role in the neural regulation of physiological functions by tuning the level of ATPcarried energy that is needed for neuronal functions, such as neurotransmission and/or intracellular signaling.

Reproductive Biology and

Ecto-nucleoside triphosphate diphosphohydrolase 3 in the ventral and lateral hypothalamic area of... more

Bisphenol A influences oestrogen- and thyroid hormone-regulated thyroid hormone receptor expression in rat cerebellar cell culture

Acta Veterinaria Hungarica, 2016

Thyroid hormones (THs) and oestrogens are crucial in the regulation of cerebellar development. TH... more Thyroid hormones (THs) and oestrogens are crucial in the regulation of cerebellar development. TH receptors (TRs) mediate these hormone effects and are regulated by both hormone families. We reported earlier that THs and oestradiol (E2) determine TR levels in cerebellar cell culture. Here we demonstrate the effects of low concentrations (10–10 M) of the endocrine disruptor (ED) bisphenol A (BPA) on the hormonal (THs, E2) regulation of TRα,β in rat cerebellar cell culture. Primary cerebellar cell cultures, glia-containing and glia-destroyed, were treated with BPA or a combination of BPA and E2 and/or THs. Oestrogen receptor and TH receptor mRNA and protein levels were determined by real-time qPCR and Western blot techniques. The results show that BPA alone decreases, while BPA in combination with THs and/or E2 increases TR mRNA expression. In contrast, BPA alone increased receptor protein expressions, but did not further increase them in combination with THs and/or E2. The modulatory...

Hypothalamic Sidedness in Mitochondrial Metabolism: New Perspectives

Reproductive Sciences, 2014

Morphofunctional changes in hypothalamic neurons are highly energy dependent and rely on mitochon... more Morphofunctional changes in hypothalamic neurons are highly energy dependent and rely on mitochondrial metabolism. Therefore, mitochondrial adenosine triphosphate production plays a permissive role in hypothalamic regulatory events. Here, we demonstrated that in the female rat hypothalamus, mitochondrial metabolism and tissue oxygenation show an asymmetric lateralization during the estrous cycle. This asymmetry was not detected in males. The observed sidedness suggests that estrous cycle-linked hypothalamic functions in females are based on hemispheric distinction. The novel concept of hypothalamic asymmetry necessitates the revision of hypothalamic neural circuits, synaptic reorganization, and the role of hypothalamic sides in the regulation of integrated homeostatic functions.

In memorioam Prof. Dr. P�ter Rudas (1951-2006)

Acta Physiol Hung, 2006

A reprodukció és táplálékfelvétel centrális irányítása: a hipotalamusz aszimmetrikus mu′köése

Magyar Allatorvosok Lapja, 2017

A maternalis immunitás átadása kérozokben: Rövidített másodközlés

Magyar Allatorvosok Lapja, 2004

Heterogeneity of bovine IgG2

A szarvasmarha neonatalis Fc-receptorának (bFcRn) togybeli expressziója és IgG-köto képessége

Endocrine Disruptors Induced Distinct Expression of Thyroid and Estrogen Receptors in Rat versus Mouse Primary Cerebellar Cell Cultures

Brain Sciences

The endocrine system of animals consists of fine-tuned self-regulating mechanisms that maintain t... more The endocrine system of animals consists of fine-tuned self-regulating mechanisms that maintain the hormonal and neuronal milieu during tissue development. This complex system can be influenced by endocrine disruptors (ED)—substances that can alter the hormonal regulation even in small concentrations. By now, thousands of substances—either synthesized by the plastic, cosmetic, agricultural, or medical industry or occurring naturally in plants or in polluted groundwater—can act as EDs. Their identification and testing has been a hard-to-solve problem; Recent indications that the ED effects may be species-specific just further complicated the determination of biological ED effects. Here we compare the effects of bisphenol-A, zearalenone, and arsenic (well-known EDs) exerted on mouse and rat neural cell cultures by measuring the differences of the ED-affected neural estrogen- and thyroid receptors. EDs alters the receptor expression in a species-like manner detectable in the magnitude ...

Comparison of Individual and Combined Effects of Four Endocrine Disruptors on Estrogen Receptor Beta Transcription in Cerebellar Cell Culture: The Modulatory Role of Estradiol and Triiodo-Thyronine

International Journal of Environmental Research and Public Health, Jun 22, 2016

Background: Humans and animals are continuously exposed to a number of environmental substances t... more Background: Humans and animals are continuously exposed to a number of environmental substances that act as endocrine disruptors (EDs). While a growing body of evidence is available to prove their adverse health effects, very little is known about the consequences of simultaneous exposure to a combination of such chemicals; Methods: Here, we used an in vitro model to demonstrate how exposure to bisphenol A, zearalenone, arsenic, and 4-methylbenzylidene camphor, alone or in combination, affect estrogen receptor β (ERβ) mRNA expression in primary cerebellar cell cultures. Additionally, we also show the modulatory role of intrinsic biological factors, such as estradiol (E2), triiodo-thyronine (T3), and glial cells, as potential effect modulators; Results: Results show a wide diversity in ED effects on ERβ mRNA expression, and that the magnitude of these ED effects highly depends on the presence or absence of E2, T3, and glial cells; Conclusion: The observed potency of the EDs to influence ERβ mRNA expression, and the modulatory role of E2, T3, and the glia suggests that environmental ED effects may be masked as long as the hormonal milieu is physiological, but may tend to turn additive or superadditive in case of hormone deficiency.

Effect of environmental temperature on pigs infected with Pasteurella multocida type A

PubMed, 1987

Percentage of animals with hypothalamic asymmetry in state 3 mitochondrial respiration rate (<i>mrr</i>)

<p>E2 treatment, regardless of satiety states, caused significantly higher proportion of si... more <p>E2 treatment, regardless of satiety states, caused significantly higher proportion of sided animals (Fisher’s exact test, *: p<0.05). In absence of E2, 24 hours food restriction further reduced the extent of hypothalamic asymmetry. Experimental groups: E2+<i>ad lib</i>: estrogen treated, <i>ad libitum</i> fed animals (n = 5); E2+fasted: estrogen treated, fasted animals (n = 6); S+<i>ad lib</i>: vehicle injected, <i>ad libitum</i> fed animals (n = 5); S+fasted: vehicle injected, fasted animals (n = 4). Sidedness was considered if the difference between the left and right hypothalamic sides of the individual was 20% or higher.</p

RESEARCH ARTICLE Estrogen- and Satiety State-Dependent Metabolic Lateralization in the Hypothalamus of Female Rats

Hypothalamus is the highest center and the main crossroad of numerous homeostatic regu-latory pat... more Hypothalamus is the highest center and the main crossroad of numerous homeostatic regu-latory pathways including reproduction and energy metabolism. Previous reports indicate that some of these functions may be driven by the synchronized but distinct functioning of the left and right hypothalamic sides. However, the nature of interplay between the hemi-spheres with regard to distinct hypothalamic functions is still unclear. Here we investigated the metabolic asymmetry between the left and right hypothalamic sides of ovariectomized female rats by measuring mitochondrial respiration rates, a parameter that reflects the inten-sity of cell and tissue metabolism. Ovariectomized (saline injected) and ovariectomized +estrogen injected animals were fed ad libitum or fasted to determine 1) the contribution of estrogen to metabolic asymmetry of hypothalamus; and 2) whether the hypothalamic asym-metry is modulated by the satiety state. Results show that estrogen-priming significantly increased...

$Research paper thumbnail of Preparation of purified perikaryal and synaptosomal mitochondrial fractions from relatively small hypothalamic brain samples$

Preparation of purified perikaryal and synaptosomal mitochondrial fractions from relatively small hypothalamic brain samples

MethodsX, 2016

In order to measure the activity of neuronal mitochondria, a representative proof of neuronal pro... more In order to measure the activity of neuronal mitochondria, a representative proof of neuronal processes, physiologically relevant mitochondrial samples need to be gained as simply as possible. Existing methods are, however, either for tissue samples of large size and/or homogenous microstructures only, or are not tested for mitochondrial function measurements. In the present article we describe a gradient fractionation method to isolate viable and well-coupled mitochondria from relatively heterogeneous histological microstructures such as the hypothalamus. With this new method, we are able to isolate a sufficient amount of functional mitochondria for determination of respiratory activity, in a short period of time, using affordable equipment. Verified by electron microscopy, our method separates highly enriched and well-preserved perikaryal and

Morpho-functional analysis of ecto-nucleoside triphosphate diphosphohydrolases in hypothalamic neurons

Frontiers in Systems Neuroscience, 2009

ABSTRACT The recently discovered ecto-nucleoside triphosphate diphosphohydrolases (NTPDases) are ... more ABSTRACT The recently discovered ecto-nucleoside triphosphate diphosphohydrolases (NTPDases) are mostly transmembrane proteins hydrolyzing ATP and producing substrates for the different purinergic receptors. The NTPDase family consists of 8 isoenzymes. In the central nervous system NTPDase1-3 isoenzymes were detected. In our earlier experiments, we mapped the tissue distribution of NTPDase3 in the central nervous system. NTPDase3 immunoreactivity (IR) was detected exclusively in neurons. Further immunohistochemical and electronmicroscopic studies in the ventrobasal hypothalamic area revealed that NTPDase3 is exclusively associated with excitatory neurons; either as a transmembrane protein or as a protein associated with subcellular organella (e.g. associated with ribosomes, in the matrix of certain mitochondria). Our goal was the further functional characterization of hypothalamic NTPDases. 1) With respect to the estrogen sensitivity of the ventrobasal hypothalamus and to its neuroendocrine role in reproductive processes, we examined whether the expression of NTPDase3 is estrogen dependent. 2) As NTPDase3 IR mitochondria were abundant in the hypothalamic excitatory axon terminals, we tested whether mitochondrial respiration in the hypothalamic synaptosoma can be influenced by applying an NTPDase blocking agent. We show that 1) the hypothalamic expression of NTPDase3 is considerably influenced by the actual estrogen level; 2) NTPDase blocking significantly decreases type 3 mitochondrial respiration and the total mitochondrial respiratory capacity. In conclusion, our results indicate that estrogen regulates the mitochondrial expression of NTPDases and therefore influences the mitochondrial energy (ATP) supply necessary for excitatory neurotransmission in the ventrobasal hypothalamus.

Comparison of individual and combined effects of procainamide and amiodarone in patients with sustained ventricular tachyarrhythmias

Circulation, 1988

To compare the individual and combined electrophysiological effects of amiodarone and procainamid... more To compare the individual and combined electrophysiological effects of amiodarone and procainamide, 35 patients with sustained ventricular arrhythmias underwent programmed stimulation in the control state, after procainamide (mean concentration, 8.7 +/- 2.8 micrograms/ml), after 13 +/- 2 days of amiodarone (1,400 mg/day x 7 days, then 400 mg/day), and after amiodarone with procainamide (mean procainamide concentration, 7.8 +/- 2.2 micrograms/ml). Sustained ventricular tachycardia (VT) was inducible in all 35 patients during treatment with procainamide alone and with amiodarone alone. Procainamide and amiodarone similarly increased the VT cycle length (+68 vs. +61 msec), the corrected QT interval (+63 vs. +49 msec), and the ventricular effective refractory period measured at paced cycle lengths of 600-550 msec (+23 vs. +21 msec) and 400 msec (+25 vs. +23 msec). Procainamide had a more pronounced effect on QRS duration than amiodarone during sinus rhythm (+18 vs. +8 msec, p less than ...

Oestrogens in the mammalian brain: From conception to adulthood — A review

Acta Veterinaria Hungarica, 2007

Environmental and plant oestrogens have been identified as compounds that when ingested, disrupt ... more Environmental and plant oestrogens have been identified as compounds that when ingested, disrupt the physiological pathways of endogenous oestrogen actions and thus, act as agonists or antagonists of oestrogen. Although the risks of exposure to exogenous oestrogens (ExEs) are subject to scientific debate, the question of how ExE exposure affects the central nervous system remains to be answered. We attempt to summarise the mechanisms of oestrogenic effects in the central nervous tissue with the purpose to highlight the avenues potentially used by ExEs. The genomic and rapid, non-genomic cellular pathways activated by oestrogen are listed and discussed together with the best known interneuronal mechanisms of oestrogenic effects. Because the effects of oestrogen on the brain seem to be age dependent, we also found it necessary to put the age-dependent oestrogenic effects in parallel to their intra-and intercellular mechanisms of action. Finally, considering the practical risks of human ExE exposure, we briefly discuss the human significance of this matter. We believe this short review of the topic became necessary because recent data suggest new fields and pathways for endogenous oestrogen actions and have generated the concern that the hidden exposure of humans and domestic animal species to ExEs may also exert its beneficial and/or adverse effects through these avenues.

Glycogenic induction of thyroid hormone conversion and leptin system activation in the liver of postpartum dairy cows

Acta Veterinaria Hungarica, 2009

In the regulation of energy metabolism, the liver plays an important role in the reinforcement of... more In the regulation of energy metabolism, the liver plays an important role in the reinforcement of energy production. In periparturient cows the energy homeostasis turns into a negative energy balance that may shift the physiological regulation of energy balance towards pathological processes. Propylene glycol (PG), as a complementary source of energy used in the nutrition of dairy cows, alters systemic thyroid hormone economy; however, the exact mechanism through which highly glycogenic feed supplements impact liver metabolism is little known. Previous studies showed that only leptin receptors are expressed in the liver of cows, and now we report that leptin mRNA is expressed in the liver of cows as well. The present results show that the mRNA of leptin and its receptors are differentially modulated by the increased energy content of the feed consumed. Simultaneous changes in hepatic type I deiodinase activity suggest that hepatic modulation of the leptin system by PG supplementatio...

BioMed Central Hypothesis NTPDases in the neuroendocrine hypothalamus: Possible energy

regulators of the positive gonadotrophin feedback

NTPDases in the neuroendocrine hypothalamus: Possible energy regulators of the positive gonadotrophin feedback

Reproductive Biology and Endocrinology, 2009

Background: Brain-derived ectonucleoside triphosphate diphosphohydrolases (NTPDases) have been kn... more Background: Brain-derived ectonucleoside triphosphate diphosphohydrolases (NTPDases) have been known as plasma membrane-incorporated enzymes with their ATP-hydrolyzing domain outside of the cell. As such, these enzymes are thought to regulate purinergic intercellular signaling by hydrolyzing ATP to ADP-AMP, thus regulating the availability of specific ligands for various P2X and P2Y purinergic receptors. The role of NTPDases in the central nervous system is little understood. The two major reasons are the insufficient knowledge of the precise localization of these enzymes in neural structures, and the lack of specific inhibitors for the various NTPDases. To fill these gaps, we recently studied the presence of neuron-specific NTPDase3 in the mitochondria of hypothalamic excitatory neurons by morphological and functional methods. Results from those studies suggested that intramitochondrial regulation of ATP levels may play a permissive role in the neural regulation of physiological functions by tuning the level of ATPcarried energy that is needed for neuronal functions, such as neurotransmission and/or intracellular signaling.

Reproductive Biology and

Ecto-nucleoside triphosphate diphosphohydrolase 3 in the ventral and lateral hypothalamic area of... more

Bisphenol A influences oestrogen- and thyroid hormone-regulated thyroid hormone receptor expression in rat cerebellar cell culture

Acta Veterinaria Hungarica, 2016

Thyroid hormones (THs) and oestrogens are crucial in the regulation of cerebellar development. TH... more Thyroid hormones (THs) and oestrogens are crucial in the regulation of cerebellar development. TH receptors (TRs) mediate these hormone effects and are regulated by both hormone families. We reported earlier that THs and oestradiol (E2) determine TR levels in cerebellar cell culture. Here we demonstrate the effects of low concentrations (10–10 M) of the endocrine disruptor (ED) bisphenol A (BPA) on the hormonal (THs, E2) regulation of TRα,β in rat cerebellar cell culture. Primary cerebellar cell cultures, glia-containing and glia-destroyed, were treated with BPA or a combination of BPA and E2 and/or THs. Oestrogen receptor and TH receptor mRNA and protein levels were determined by real-time qPCR and Western blot techniques. The results show that BPA alone decreases, while BPA in combination with THs and/or E2 increases TR mRNA expression. In contrast, BPA alone increased receptor protein expressions, but did not further increase them in combination with THs and/or E2. The modulatory...

Hypothalamic Sidedness in Mitochondrial Metabolism: New Perspectives

Reproductive Sciences, 2014

Morphofunctional changes in hypothalamic neurons are highly energy dependent and rely on mitochon... more Morphofunctional changes in hypothalamic neurons are highly energy dependent and rely on mitochondrial metabolism. Therefore, mitochondrial adenosine triphosphate production plays a permissive role in hypothalamic regulatory events. Here, we demonstrated that in the female rat hypothalamus, mitochondrial metabolism and tissue oxygenation show an asymmetric lateralization during the estrous cycle. This asymmetry was not detected in males. The observed sidedness suggests that estrous cycle-linked hypothalamic functions in females are based on hemispheric distinction. The novel concept of hypothalamic asymmetry necessitates the revision of hypothalamic neural circuits, synaptic reorganization, and the role of hypothalamic sides in the regulation of integrated homeostatic functions.

In memorioam Prof. Dr. P�ter Rudas (1951-2006)

Acta Physiol Hung, 2006

A reprodukció és táplálékfelvétel centrális irányítása: a hipotalamusz aszimmetrikus mu′köése

Magyar Allatorvosok Lapja, 2017

A maternalis immunitás átadása kérozokben: Rövidített másodközlés

Magyar Allatorvosok Lapja, 2004

Heterogeneity of bovine IgG2

A szarvasmarha neonatalis Fc-receptorának (bFcRn) togybeli expressziója és IgG-köto képessége

Endocrine Disruptors Induced Distinct Expression of Thyroid and Estrogen Receptors in Rat versus Mouse Primary Cerebellar Cell Cultures

Brain Sciences

The endocrine system of animals consists of fine-tuned self-regulating mechanisms that maintain t... more The endocrine system of animals consists of fine-tuned self-regulating mechanisms that maintain the hormonal and neuronal milieu during tissue development. This complex system can be influenced by endocrine disruptors (ED)—substances that can alter the hormonal regulation even in small concentrations. By now, thousands of substances—either synthesized by the plastic, cosmetic, agricultural, or medical industry or occurring naturally in plants or in polluted groundwater—can act as EDs. Their identification and testing has been a hard-to-solve problem; Recent indications that the ED effects may be species-specific just further complicated the determination of biological ED effects. Here we compare the effects of bisphenol-A, zearalenone, and arsenic (well-known EDs) exerted on mouse and rat neural cell cultures by measuring the differences of the ED-affected neural estrogen- and thyroid receptors. EDs alters the receptor expression in a species-like manner detectable in the magnitude ...