Oxytocin Receptor Gene Expression Research Articles

Selective alterations of endocannabinoid system genes expression in obsessive compulsive disorder

Obsessive Compulsive Disorder (OCD) is listed as one of the top 10 most disabling neuropsychiatric conditions in the world. The neurobiology of OCD has not been completely understood and efforts are needed in order to develop new treatments. Beside the classical neurotransmitter systems and signalling pathways implicated in OCD, the possible involvement of the endocannabinoid system (ECS) has emerged in pathophysiology of OCD. We report here selective downregulation of the genes coding for enzymes allowing the synthesis of the endocannabinoids. We found reduced DAGLα and NAPE-PLD in blood samples of individuals with OCD (when compared to healthy controls) as well as in the amygdala complex and prefrontal cortex of dopamine transporter (DAT) heterozygous rats, manifesting compulsive behaviours. Also mRNA levels of the genes coding for cannabinoid receptors type 1 and type 2 resulted downregulated, respectively in the rat amygdala and in human blood. Moreover, NAPE-PLD changes in gene expression resulted to be associated with an increase in DNA methylation at gene promoter, and the modulation of this gene in OCD appears to be correlated to the progression of the disease. Finally, the alterations observed in ECS genes expression appears to be correlated with the modulation in oxytocin receptor gene expression, consistently with what recently reported. Overall, we confirm here a role for ECS in OCD at both preclinical and clinical level. Many potential biomarkers are suggested among its components, in particular NAPE-PLD, that might be of help for a prompt and clear diagnosis.

The Multifaceted Role of Oxytocinergic System and OXTR Gene.

The article explores the multifaceted role of the neuropeptide oxytocin in human behavior and its connection to the oxytocin receptor ( OXTR ) gene. Oxytocin, produced in specific brain nuclei, is implicated in emotional, social, and maternal behaviors, stress reduction, uterine contraction during childbirth, and lactation. The OXTR gene, located on chromosome 3, encodes oxytocin receptors found in various body parts, including critical brain regions associated with social behaviors. The article delves into studies on rodents, revealing correlations between OXTR gene expression and pair bonding in the prefrontal cortex and social behavior regulation in the amygdala. The discussion extends to the impact of oxytocin on social support-seeking behavior, focusing on a specific genetic variation, rs53576. The article explores how this genetic variation influences empathy, stress reactivity, and susceptibility to disorders such as autism and social anxiety. Furthermore, the article examines structural and functional changes in the brain associated with OXTR gene variations. It discusses the role of DNA methylation in influencing oxytocin receptor availability, affecting social perception and responsiveness to negative stimuli. The article also highlights the oxytocinergic system's involvement in disorders such as autism and social anxiety, emphasizing the interplay between genetics and environmental factors. The article also touches on the potential therapeutic use of exogenous oxytocin in mitigating symptoms associated with these disorders. In summary, the article underscores the intricate relationship between oxytocin, the OXTR gene, and diverse aspects of human behavior, providing insights into social bonding, perception, and the development of behavioral disorders.

Effect of exogenous oxytocin on the expression of oxytocin receptor gene and uterine involution in local Iraqi cows

The present work aimed to study the effect of exogenous oxytocin injection on the expression of the oxytocin receptor gene and the duration of uterine involution in the local Iraqi breed of Karradi cows. Twenty cows were divided into two groups. The first group was considered a control; the second group was injected with 100 IU/IM of oxytocin twice weekly for four weeks postpartum. The uterine involution velocity was monitored using ultrasonography by measuring the endometrium thickness, ovarian diameter, cervix diameter, uterine horns diameter, serum progesterone, and estrogen levels by indirect ELISA, and the expression of oxytocin receptor gene was monitored by conventional PCR. The result of the treated group showed that the progesterone concentration was significantly decreased. The estrogen concentration was significantly increased. Moreover, the endometrium thickness was significantly decreased in the second, third, and fourth weeks, also, the ovarian diameter was significantly decreased in the first and second weeks, but it has significantly increased in the fourth week. In addition, the cervix diameter was significantly decreased in the first and second weeks, and the uterine horns diameter was significantly decreased in all weeks compared to the control group at POTXRs gene overexpression, where OTXRs gene expression was increased in the oxytocin group in comparison with the control group. This result was present in a coordinated manner with the result of the estrus cycle and ovarian reactivation. We conclude that injection of exogenous oxytocin at 100 IU/IM twice weekly for four weeks postpartum will increase the expression of the oxytocin receptor gene, leading to a decrease in the duration of uterine involution. Accelerate the occurrence of estrus in the local Iraqi breed of Karradi cows.

Regulation of oxytocin receptor gene expression in obsessive\u2013compulsive disorder: a possible role for the microbiota-host epigenetic axis

BackgroundObsessive–compulsive disorder (OCD) is a prevalent and severe clinical condition. Robust evidence suggests a gene-environment interplay in its etiopathogenesis, yet the underlying molecular clues remain only partially understood. In order to further deepen our understanding of OCD, it is essential to ascertain how genes interact with environmental risk factors, a cross-talk that is thought to be mediated by epigenetic mechanisms. The human microbiota may be a key player, because bacterial metabolites can act as epigenetic modulators. We analyzed, in the blood and saliva of OCD subjects and healthy controls, the transcriptional regulation of the oxytocin receptor gene and, in saliva, also the different levels of major phyla. We also investigated the same molecular mechanisms in specific brain regions of socially isolated rats showing stereotyped behaviors reminiscent of OCD as well as short chain fatty acid levels in the feces of rats.ResultsHigher levels of oxytocin receptor gene DNA methylation, inversely correlated with gene expression, were observed in the blood as well as saliva of OCD subjects when compared to controls. Moreover, Actinobacteria also resulted higher in OCD and directly correlated with oxytocin receptor gene epigenetic alterations. The same pattern of changes was present in the prefrontal cortex of socially-isolated rats, where also altered levels of fecal butyrate were observed at the beginning of the isolation procedure.ConclusionsThis is the first demonstration of an interplay between microbiota modulation and epigenetic regulation of gene expression in OCD, opening new avenues for the understanding of disease trajectories and for the development of new therapeutic strategies.

Oxytocin receptor expression patterns in the human brain across development.

Oxytocin plays a vital role in social behavior and homeostatic processes, with animal models indicating that oxytocin receptor (OXTR) expression patterns in the brain influence behavior and physiology. However, the developmental trajectory of OXTR gene expression is unclear. By analyzing gene expression data in human post-mortem brain samples, from the prenatal period to late adulthood, we demonstrate distinct patterns of OXTR gene expression in the developing brain, with increasing OXTR expression along the course of the prenatal period culminating in a peak during early childhood. This early life OXTR expression peak pattern appears slightly earlier in a comparative macaque sample, which is consistent with the relative immaturity of the human brain during early life compared to macaques. We also show that a network of genes with strong spatiotemporal couplings with OXTR is enriched in several psychiatric illness and body composition phenotypes. Taken together, these results demonstrate that oxytocin signaling plays an important role in a diverse set of psychological and somatic processes across the lifespan.

Paternal stress in rats increased oxytocin, oxytocin receptor, and arginine vasopressin gene expression in the male offspring amygdala with no effect on their social interaction behaviors

Environmental and hereditary factors play roles in shaping the personality of offspring which are often associated with gene expression alterations. The long-term effects of the environment that are modulated by the epigenetic mechanisms can be even transmitted to the next generations. This study aimed to investigate the effects of paternal stress, such as paternal aggression and food deprivation, on the social interaction behaviors of offspring in adulthood and the expression of genes that are associated with these behaviors. The intruder-resident method, followed by an electric shock, was used to induce aggression in male Wistar rats before mating. To induce food deprivation, father rats were given 10 g pellets every day without restriction on water consumption for 2 weeks before mating. Social interactions of the male offspring were evaluated at the age of 8 weeks using a three-chamber social interaction test. Real-time PCR was applied to quantify the expression levels of oxytocin (OXT), oxytocin receptor (OXTR), and arginine vasopressin (AVP) genes in the amygdala of offspring. One-way analysis of variance was used to compare the means of experimental groups. The results did not show significant changes in the social interaction behaviors for the offspring of aggressive and food-deprived fathers compared to the control group. However, molecular investigations indicated increased levels of OXT, OXTR, and AVP gene expression in the offspring amygdala of aggressive and food-deprived fathers. The results showed that paternal stress, such as aggression and food deprivation, induced gene expression alterations in the offspring, although they did not affect their social interaction behaviors.

Genetic, epigenetic, and environmental factors controlling oxytocin receptor gene expression

BackgroundThe neuropeptide oxytocin regulates mammalian social behavior. Disruptions in oxytocin signaling are a feature of many psychopathologies. One commonly studied biomarker for oxytocin involvement in psychiatric diseases is DNA methylation at the oxytocin receptor gene (OXTR). Such studies focus on DNA methylation in two regions of OXTR, exon 3 and a region termed MT2 which overlaps exon 1 and intron 1. However, the relative contribution of exon 3 and MT2 in regulating OXTR gene expression in the brain is currently unknown.ResultsHere, we use the prairie vole as a translational animal model to investigate genetic, epigenetic, and environmental factors affecting Oxtr gene expression in a region of the brain that has been shown to drive Oxtr related behavior in the vole, the nucleus accumbens. We show that the genetic structure of Oxtr in prairie voles resembles human OXTR. We then studied the effects of early life experience on DNA methylation in two regions of a CpG island surrounding the Oxtr promoter: MT2 and exon 3. We show that early nurture in the form of parental care results in DNA hypomethylation of Oxtr in both MT2 and exon 3, but only DNA methylation in MT2 is associated with Oxtr gene expression. Network analyses indicate that CpG sites in the 3′ portion of MT2 are most highly associated with Oxtr gene expression. We also identify two novel SNPs in exon 3 of Oxtr in prairie voles and a novel alternative transcript originating from the third intron of the gene. Expression of the novel alternative transcript is associated with genotype at SNP KLW2.ConclusionsThese results identify putative regulatory features of Oxtr in prairie voles which inform future studies examining OXTR in human social behaviors and disorders. These studies indicate that in prairie voles, DNA methylation in MT2, particularly in the 3′ portion, is more predictive of Oxtr gene expression than DNA methylation in exon 3. Similarly, in human temporal cortex, we find that DNA methylation in the 3′ portion of MT2 is associated with OXTR expression. Together, these results suggest that among the CpG sites studied, DNA methylation of MT2 may be the most reliable indicator of OXTR gene expression. We also identify novel features of prairie vole Oxtr, including SNPs and an alternative transcript, which further develop the prairie vole as a translational model for studies of OXTR.

Maternal blood and amnionic oxytocin receptor gene expression and serum oxytocin levels in preterm birth: a case-control study

BACKGROUND: The oxytocin (OXT)-oxytocin receptor (OXTR) system provides promising candidate gene for studies of genetic contributions to prematurity. OBJECTIVE: Quantification and comparison of oxytocin receptor (OXTR) gene expression and serum OXT levels in the blood and amnion of women delivering preterm and evaluation of the correlation between OXTR gene expression in blood and amnion with serum OXT levels in them. METHODS: 70 pregnant women in spontaneous labor delivering vaginally preterm i.e < 37 weeks and equal number of matched controls delivering spontaneously at term (37-42 weeks) were recruited. Maternal serum OXT levels taken in active stage of labor (i.e 4 cm cervical dilatation) were quantified by ELISA. Gene expression studies in the maternal blood and amnion were done by using real time quantitative polymerase chain reaction (RT-qPCR). RESULTS: The mean serum OXT level in PTL was 48.56 +- 6.97 pg/ml; significantly higher than in controls (43.00 +- 3.96 pg/ml), p<0.001. OXTR gene expression both in maternal blood (2.5 times) and amnion (3.5 times) were significantly higher in PTL. A significant positive correlation was observed between serum OXT levels and OXTR gene expression in amnion (r = -0.190, p = 0.025). CONCLUSIONS: The serum OXT levels and OXTR gene expression in amnion surge significantly in active phase of PTL. Thus, amnion probably links OXT-PTGs autocrine paracrine circuit to facilitate PTL. Future studies are needed to devise better OXTR receptor antagonists preferably acting on amnionic OXTRs to prevent PTL. KEYWORDS: Preterm birth, Preterm labor, Oxytocin, Oxytocin receptor, Placenta, Amnion

Right Posterior Insula and Putamen Volume Mediate the Effect of Oxytocin Receptor Polygenic Risk for Autism Spectrum Disorders on Reward Dependence in Healthy Adults.

Much evidence indicates the influence of the oxytocin receptor (OXTR) gene on autism spectrum disorders (ASDs), a set of disorders characterized by a range of deficits in prosocial behaviors, which are closely related to the personality trait of reward dependence (RD). However, we do not know the effect of the OXTR polygenic risk score for ASDs (OXTR-PRSASDs) on RD and its underlying neuroanatomical substrate. Here, we aimed to investigate associations among the OXTR-PRSASDs, gray matter volume (GMV), and RD in two independent datasets of healthy young adults (n = 450 and 540). We found that the individuals with higher OXTR-PRSASDs had lower RD and significantly smaller GMV in the right posterior insula and putamen. The GMV of this region showed a positive correlation with RD and a mediation effect on the association between OXTR-PRSASDs and RD. Moreover, the correlation map between OXTR-PRSASDs and GMV showed spatial correlation with OXTR gene expression. All results were highly consistent between the two datasets. These findings highlight a possible neural pathway by which the common variants in the OXTR gene associated with ASDs may jointly impact the GMV of the right posterior insula and putamen and further affect the personality trait of RD.

A Novel Link between the Oxytocin Receptor Gene and Impulsivity

Impulsivity includes hasty actions, social intrusiveness or premature decision-making. Neuropeptides like oxytocin alleviate haste and anxiety, and affect fear conditioning. However, no investigations have been done via gene-network based approach with cognitive and interventional genetic association studies to scrutinize the link between impulsive behavior and oxytocin. Here, interactive gene network and pathways associated with impulsivity were reconstructed, and serotonin transporter gene (SLC6A4) and serotoninergic synaptic transmission were identified as the most central gene and pathway related to impulsivity. Young healthy males received intranasal oxytocin or placebo, and impulsivity was evaluated via go/no-go test. Test performance scores then were analyzed based on commission and omission errors, response inhibition and reaction time. Blood DNA was extracted and a 761 bp intronic region in oxytocin receptor (OXTR) gene was amplified and sequenced using PCR-pyrosequencing. Employing Haploview, haplotypes and linkage disequilibrium (LD) pattern among all SNPs in the target sequence were determined based on D′ and LOD values, and rs2254298 with the highest LD was indicated as the tag SNP. Oxytocin group and participants with GG genotype showed a significantly decreased commission error and increased inhibition. This means that oxytocin alleviated impulsive behavior, and subjects with GG genotype had lower rate of impulsivity than those with GA and AA genotypes. rs2254298 may modulate the function or expression of the OXTR gene, implying that G allele may increase the expression of OXTR gene compared to A allele. We suggest that intranasal oxytocin may notably moderate impulsive behavior and tendency to make hasty or premature decisions.

Oxytocin Reduces Intravesical Pressure in Anesthetized Female Rats: Action on Oxytocin Receptors of the Urinary Bladder.

Urinary bladder dysfunction affects several people worldwide and shows higher prevalence in women. Micturition is dependent on the Barrington’s nucleus, pontine urine storage center and periaqueductal gray matter, but other brain stem areas are involved in the bladder regulation. Neurons in the medulla oblongata send projections to hypothalamic nuclei as the supraoptic nucleus, which synthetizes oxytocin and in its turn, this peptide is released in the circulation. We investigated the effects of intravenous injection of oxytocin (OT) on the urinary bladder in sham and ovariectomized rats. We also evaluated the topical (in situ) action of OT on intravesical pressure (IP) as well as the existence of oxytocin receptors in the urinary bladder. In sham female Wistar rats, anesthetized with isoflurane, intravenous infusion of OT (10 ng/kg) significantly decreased the IP (–47.5 ± 1.2%) compared to saline (3.4 ± 0.7%). Similar effect in IP was observed in ovariectomized rats after i.v. OT (–41.9 ± 2.9%) compared to saline (0.5 ± 0.6%). Topical administration (in situ) of 0.1 mL of OT (1.0 ng/mL) significantly reduced the IP (22.3.0 ± 0.6%) compared to saline (0.9 ± 0.7%). We also found by qPCR that the gene expression of oxytocin receptor is present in this tissue. Blockade of oxytocin receptors significantly attenuated the reduction in IP evoked by oxytocin i.v. or in situ. Therefore, the findings suggest that (1) intravenous oxytocin decreases IP due to bladder relaxation and (2) OT has local bladder effect, binding directly in receptors located in the bladder.

799: Does cholesterol exposure of myometrial cells affect oxytocin receptor gene expression and downstream signaling?

Obesity increases the risk of dysfunctional labor and cesarean delivery. The etiology still remains unclear. Obesity has a positive correlation to elevated blood cholesterol levels. In animal models and in vitro studies, high cholesterol levels decreases uterine contractility. The objective of this study is to investigate the effect of cholesterol on oxytocin receptor expression and downstream signaling using a human myometrial cell line. Immortalized human myometrial, PHM1-41 cells were exposed to either 0 (vehicle) or 50 μg/ml of cholesterol for 24 hours; cytotoxicity assays confirmed this dose was non-cytotoxic. Vehicle and cholesterol exposed cells were then treated with 1μM/ml of oxytocin (OXT) for 2 hours. The expression of mRNAs encoding oxytocin receptor (OXTR) and select downstream signaling contractility genes - Protein kinase C (PRKCA), Map kinase (MAP2k2), gap junction gene Debrin-1 (DBN1) and select key relaxation genes - Adenylate cyclase 1 (ADCY1v1) and Adrenergic receptor B2 (ADRB2) were analyzed by quantitative RT-PCR. Differences in mRNA levels between different groups (control, cholesterol only, oxytocin only, cholesterol + oxytocin) were evaluated. The mRNA expression of OXTR, key downstream contractility genes - PRKCA, gap junction gene - DBN1 and key relaxation genes - ADCY1v1 and ADRB2 were identified in control, cholesterol exposed, OXT-exposed and OXT + cholesterol groups, whereas the mRNA expression for Map kinase-2 (MAP2k2) receptor was only identified in OXT-exposed cells. Cholesterol treatment (±OXT) had no effect on the expression of mRNAs for OXTR, downstream contractility genes, gap junction genes and relaxation genes by PHM1-41 cells. Our results suggest that cholesterol exposure of PHM1-41 myometrial cells alone doesn’t affect the mRNA expression of OXTR oxytocin receptor expression or downstream contractility and relaxation signaling genes.

Impact of housing conditions on social behavior, neuroimmune markers, and oxytocin receptor expression in aged male and female Fischer 344 rats.

Aging is associated with a substantial decline in social behavior, whereas positive social interaction can improve overall health in aged individuals. In laboratory rodents, manipulations of the social environment across the lifespan have been shown to affect social behavior. Therefore, we examined the effects of long-term (5-6 weeks) housing conditions (alone, with one adult, or with two adults) on social behavior and the expression of neuroinflammation-related genes as well as oxytocin receptor (OXTR) gene expression in brain areas associated with social behavior regulation in aged male and female Fischer (F) 344 rats. Single-housed males and females exhibited increased social investigation, relative to pair-housed rats (one aged and one adult). Triple-housed (one aged and two adults) aged males exhibited lower levels of social investigation, relative to triple-housed aged females. Aged females were more socially active that their male counterparts. Although social housing condition significantly affected social behavior in males, it had no impact on cytokine gene expression in the paraventricular nucleus of hypothalamus (PVN), bed nucleus of the stria terminalis (BNST) or medial amygdala (MeA). However, in triple-housed aged females, who exhibited social behavior comparable to their single- and pair-housed counterparts, there was a significant increase in the expression of IL-1β and IL-6 mRNA in the MeA. No changes in cytokine gene expression were observed in the PVN or BNST, indicating that the increased expression of cytokines in the MeA was not a result of a generalized increase in neuroinflammation. Single-housed males and females exhibited elevated OXTR gene expression in the BNST. Taken together, these data indicate that manipulations of the social environment in late aging significantly influenced social interactions with a novel partner and gene expression in social behavior circuits and that these effects are sex-specific.

Enhanced Response to Oxytocin in Myometrium of Proven Breeder Compared to Virgin Rats Does Not Depend on Augmented Expression of Oxytocin Receptors

ObjectiveOur overall hypothesis is that pregnancy's mechanical and hormonal stimuli induce permanent changes in the properties of uterine tissue. We have shown previously that the response to oxytocin of the non‐pregnant (NP) myometrium is more pronounced in proven breeder than in virgin animals. Our objective here was to investigate some of the possible mechanisms that could produce such difference: 1) Altered number of oxytocin receptors (OXTR); 2) Altered production of intracellular prostaglandins; 3) Altered availability of voltage gated calcium channels (VGCC).MethodVirgin (V) and proven breeder (PB) NP female 18 week old rats were staged and euthanized at proestrus. One uterine horn was dissected in strips suspended in a tissue bath containing Krebs solution (in mM, NaCl 117, KCl 4.7, NaHCO3 25, MgCl2 1.2, KH2PO4 1.2, CaCl2 2.5, glucose 11, pH= 7.4) at 37°C and bubbled with 95% O2 and 5% CO2. Dose response curves to oxytocin (10E‐10 to 10E‐5 M) were recorded in the presence of indomethacin or after exposure to a 0 CaCl2 modified Krebs. The other uterine horn was flash frozen in liquid NO2 and later used for ELISA (kit from Wuhan Fine Biotech, Wuhan China) and qRT‐PCR experiments (Taqman® gene expression assays (Life Technologies) and QuantStudio™ 5 real‐time PCR system (Applied Biosystems, Grand Island, NY) were used to examine the gene of interest mRNA expression using the comparative CT method (Schmittgen and Livak, 2008).ResultsIn the ELISA experiments, NP samples showed a barely significant (32±14%, P=0.040) elevation of OXTR in V (n = 8) vs PB myometrium. This is in open contradiction to our previous motility data. To investigate whether this inversion trend in protein level is matched at the mRNA level, we evaluated OXTR gene expression in NP strips (n=5, in quadruplicates). No significant difference was detected between V and PB expression of β‐actin (P= 0.099). Instead, a significant difference was found in the OXTR gene expression (P&lt;0.01) and the 2−ΔΔCt (RQ) was 0.18 (Min RQ=0.12, Max RQ=0.27, indicative of an 8.3 to 3.7 folds decrease in the OXTR mRNA level in PB vs V samples. On the other hand, in the presence of 10 μM indomethacin (COX inhibitor) or in the absence of extracellular calcium the differences in the responses to oxytocin in V and PB myometrial strips were attenuated (−98% and −96% respectively). This suggest important roles of second messengers activated pathways in the more robust effects of oxytocin in NP PB strips.ConclusionsWhile our previous functional experiments suggested that PB myometrium might contain a higher number of OXTR, ELISA and PCR experiments imply that the opposite might be true. The gene expression of the OXTR is frankly stronger in V, while the actual protein expression is not significantly different between V and PB. A better explanation for our pharmacological observations involves differences in the activity of channels and intracellular mechanisms activated by oxytocin, some of which we presented here and are currently under investigation.Support or Funding InformationThis study was funded by an MWU intramural research grant to MP.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Effects of Oxytocin on Cell Proliferation in a Corticotroph Adenoma Cell Line.

BackgroundOxytocin (OXT) has been reported to act as a growth regulator in various tumor cells. However, there is a paucity of data on the influence of OXT on cell proliferation of corticotroph adenomas. This study aimed to examine whether OXT affects cell growth in pituitary tumor cell lines (AtT20 and GH3 cells) with a focus on corticotroph adenoma cells.MethodsReverse transcription polymerase chain reaction and enzyme-linked immunosorbent assay were conducted with AtT20 cells to confirm the effects of OXT on hormonal activity; flow cytometry was used to assess changes in the cell cycle after OXT treatment. Moreover, the impact of OXT on proliferating cell nuclear antigen (PCNA), nuclear factor κB, and mitogen-activated protein kinase signaling pathway was analyzed by Western blot.ResultsOXT treatment of 50 nM changed the gene expression of OXT receptor and pro-opiomelanocortin within a short time. In addition, OXT significantly reduced adrenocorticotropic hormone secretion within 1 hour. S and G2/M populations of AtT20 cells treated with OXT for 24 hours were significantly decreased compared to the control. Furthermore, OXT treatment decreased the protein levels of PCNA and phosphorylated extracellular-signal-regulated kinase (P-ERK) in AtT20 cells.ConclusionAlthough the cytotoxic effect of OXT in AtT20 cells was not definite, OXT may blunt cell proliferation of corticotroph adenomas by altering the cell cycle or reducing PCNA and P-ERK levels. Further research is required to investigate the role of OXT as a potential therapeutic target in corticotroph adenomas.

Immunolocalisation and expression of oxytocin receptors and sex hormone-binding globulin in the testis and epididymis of dogs: correlation with sperm function.

The aim of this study was to confirm gene and protein expression of oxytocin receptor (OTR) and sex hormone-binding globulin (SHBG) in the testis and epididymis of dogs, correlating these data with sperm quality and production and testosterone concentrations. Positive correlations were found between OTR and SHBG expression in both the testis and epididymis. Testicular OTR expression was positively associated with plasma membrane and acrosome integrity in canine spermatozoa, whereas SHBG expression in the testis was positively correlated with various sperm characteristics, such as sperm concentration, total and progressive motility, plasma membrane integrity and acrosome integrity. Testicular expression of both OTR and SHBG was negatively correlated with low sperm mitochondrial activity. In the epididymis, SHBG expression was only positively correlated with plasma membrane integrity. Analysis of protein expression revealed that testicular OTR was positively correlated with testosterone concentrations and negatively correlated with the absence of sperm mitochondrial activity. In addition, SHBG expression in the testes was associated with epididymis SHBG expression and morphologically normal cells. Immunohistochemical (IHC) analysis revealed the presence of both OTR and SHBG in testicular smooth muscles and Leydig cells. However, in the epididymis, OTR was only located in smooth muscle cells, whereas neither IHC nor western blotting detected SHBG. Together, the results of this study suggest that OTR and SHBG play key roles in spermatogenesis and sperm maturation, being essential for male reproductive success.

Influence of cycle stage, age and endometrial biopsy score on oxytocin receptor distribution and gene expression in the cervix and uterus of non-pregnant mares

Persistent breeding-induced endometritis (PBIE) or delayed uterine clearance (DUC) are major causes of mare subfertility. Oxytocin and its receptor are thought to play significant roles in the pathogenesis of DUC but the specific roles of oxytocin receptor (OR) distribution and gene expression remain undefined.In this study both OR distribution and gene expression in the endometrium, myometrium and cervix during both luteal and non-luteal phases in non-pregnant mares (n = 27) of differing age (young: 2–9 years, n = 17; old: > 10 years, n = 10) and endometrial biopsy score were described using immunohistochemistry (IHC) and quantitative reverse-transcription polymerase chain reaction (RT-qPCR), respectively.Immunohistochemistry showed a similar pattern of OR distribution in uterus and cervix, with the exception of the glandular epithelium, absent in the cervix. Uterine ORs were localized in endometrial luminal and glandular epithelia, transmural vascular endothelium, sub-epithelial and peri-glandular stromal cells and myometrial smooth muscle cells. The OR labeling intensity was consistently greatest in the vascular endothelium. Real-time qPCR showed a higher OR gene expression in myometrium compared to cervix (P = 0.001) and endometrium (P = 0.009). There was no difference in OR gene expression between cervix and endometrium (P = 1.0). Oxytocin receptor gene expression was significantly higher during the non-luteal phase in both combined uterine tissues (endometrium and myometrium) and myometrium. Oxytocin receptor distribution and gene expression were not influenced by a mare's age or endometrial biopsy score. As endometrial biopsy score and mare age were not predictors of OR gene expression, deficient OR gene expression is unlikely to be associated with DUC.

Examination of the immunohistochemical localization and gene expression by RT-PCR of the oxytocin receptor in diabetic and non-diabetic mouse testis.

Objective(s):The aim of this study was to determine Oxytocin receptor (OTR) gene expression and localization in diabetic and non-diabetic mouse testes by RT-PCR and immunohistochemistry, respectively. Materials and Methods:In this study, 18 male BALB/c mice (8–12 weeks old) were used and divided into three groups: diabetic, sham, and control. Streptozotocin (STZ) was applied to the diabetic group and sodium citrate was administered to the sham group in the same way, however, the control group was left untouched. The testicular tissues were removed on the thirtieth day of testing; the right testis tissues were passed through a routine histologic process and sections were stained with H&E and PAS staining techniques. The avidin-biotin-peroxidase method was applied to determine OTR immunoreactivity, while the left testis tissues were used for RT-PCR. Results:It was found that the body weight had decreased in the diabetic group and the diameter of the seminiferous tubules in the said group was shorter than those of the other groups. There were no obvious differences with regard to the histologic appearance between the groups. The immunohistochemical examination showed that the OTR immunoreactivity was strong in the control and sham groups but weak in the diabetic group, and the immunoreactivity was only seen in the Leydig cells. In addition, the OTR gene expression was lower in the diabetic group than in the other groups.Conclusion:We concluded that diabetes reduces the OTR expression in the testis. It is suggested that OTR protection should be researched in diabetes for healthy reproduction and sexuality.

Insemination Dose and Site With Frozen Semen Affects the Sperm Transport and Inflammatory Response in Mares?

Persistent breeding-induced endometritis (PBIE) or delayed uterine clearance (DUC) are major causes of mare subfertility. Oxytocin and its receptor are thought to play significant roles in the pathogenesis of DUC but the specific roles of oxytocin receptor (OR) distribution and gene expression remain undefined.In this study both OR distribution and gene expression in the endometrium, myometrium and cervix during both luteal and non-luteal phases in non-pregnant mares (n = 27) of differing age (young: 2–9 years, n = 17; old: > 10 years, n = 10) and endometrial biopsy score were described using immunohistochemistry (IHC) and quantitative reverse-transcription polymerase chain reaction (RT-qPCR), respectively.Immunohistochemistry showed a similar pattern of OR distribution in uterus and cervix, with the exception of the glandular epithelium, absent in the cervix. Uterine ORs were localized in endometrial luminal and glandular epithelia, transmural vascular endothelium, sub-epithelial and peri-glandular stromal cells and myometrial smooth muscle cells. The OR labeling intensity was consistently greatest in the vascular endothelium. Real-time qPCR showed a higher OR gene expression in myometrium compared to cervix (P = 0.001) and endometrium (P = 0.009). There was no difference in OR gene expression between cervix and endometrium (P = 1.0). Oxytocin receptor gene expression was significantly higher during the non-luteal phase in both combined uterine tissues (endometrium and myometrium) and myometrium. Oxytocin receptor distribution and gene expression were not influenced by a mare's age or endometrial biopsy score. As endometrial biopsy score and mare age were not predictors of OR gene expression, deficient OR gene expression is unlikely to be associated with DUC.

Effects of oxytocin and PGF2α on uterine contractility in cows with and without metritis—An in-vitro study

The aim of this study was to investigate the effects of PGF2α and oxytocin in vitro on myometrial contractility in puerperal uteri. Thirteen puerperal uteri were removed and perfused after euthanasia of cows with (n=7) and without metritis (n=6). Measurement of uterine contractility was done using four piezoelectric crystals, which were implanted into the myometrium along the greater curvature of the uterine horn where fetal implantation occurred during the previous pregnancy. After 30min of equilibration, oxytocin (5 IU) or PGF2α (2.5mg Dinoprost) was administered randomly into both uterine arteries, and 30min later, the second administration of either oxytocin or PGF2α occurred. Treatment with oxytocin induced contractions in uteri with metritis and uteri without metritis (P<0.05). In uteri with metritis, greater uterine contractions occurred after stimulation with oxytocin than in uteri without metritis (P<0.05). Treatment with PGF2α did not (P>0.05) result in increased contractions in the uteri without metrtitis, however, induced an initial decrease in contractions followed by an increase (P<0.05) in contractions in uteri with metritis. Myometrial and endometrial gene expression of PGF2α (FPR) and oxytocin receptor (OTR) was greater (P<0.05) in uteri with metritis than in uteri without metritis. The results suggest that oxytocin, but not PGF2α, is an effective uterotonic drug in puerperal cows. Uteri in which metritis was diagnosed contracted more strongly after treatment with oxytocin than uteri in which metritis was not diagnosed. This effect was paralleled by greater gene expression of OTR as well as FPR in uteri with metritis compared with uteri in which metritis was not diagnosed.