Methylation of the Oxytocin, Oxytocin Receptor, and Vasopressin Gene Promoters in Tobacco Use Disorder during Cessation.

INTRODUCTION: Vasopressin (AVP) and oxytocin (OT) exert sex-specific effects on social pair bonding and stress reactions while also influencing craving in substance use disorders. In this regard, intranasal oxytocin (OT) and AVP antagonists present potential treatments for tobacco use disorder (TUD). Since transcription of both hormones is also regulated by gene methylation, we hypothesized sex-specific changes in methylation levels of the AVP, OT, and OT receptor (OXTR) gene during nicotine withdrawal. METHODS: The study population consisted of 49 smokers (29 males, 20 females) and 51 healthy non-smokers (25 males, 26 females). Blood was drawn at day 1, day 7, and day 14 of smoking cessation. Craving was assessed with the questionnaire on smoking urges (QSU). RESULTS: Throughout cessation, mean methylation of the OT promoter gene increased in males and decreased in females. OXTR receptor methylation decreased in females, while in males it was significantly lower at day 7. Regarding the AVP promoter, mean methylation increased in males while there were no changes in females. Using mixed linear modeling, CpG position, time point, sex, and the interaction of time point and sex as well as time point, sex, and QSU had a significant fixed effect on OT and AVP gene methylation. The interaction effect suggests that sex, time point, and QSU are interrelated, meaning that, depending on the sex, methylation could be different at different time points and vice versa. There was no significant effect of QSU on mean OXTR methylation. DISCUSSION: We identified differences at specific CpGs between controls and smokers in OT and AVP and in overall methylation of the AVP gene. Furthermore, we found sex-specific changes in mean methylation levels of the mentioned genes throughout smoking cessation, underlining the relevance of sex in the OT and vasopressin system. This is the first study on epigenetic regulation of the OT promoter in TUD. Our results have implications for research on the utility of the AVP and OT system for treating substance craving. Future studies on both targets need to analyze their effect in the context of sex, social factors, and gene regulation.

Is There A Connection Between Primary Hypophysitis and Celiac Disease?

AIM: To investigate the autoimmune and genetic relationship between primary hypophysitis (PH) and celiac disease (CD). METHODS: The study was retrospective and patients with PH followed in our clinic between 2007 and 2022 were evaluated. Clinical, endocrinologic, pathologic, and radiologic findings and treatment modalities were assessed. Patients diagnosed with CD in the Gastroenterology outpatient clinic in 2020-2022 were included in the study as a control group. Information such as sociodemographic data, year of diagnosis, human leukocyte antigen (HLA) DQ2/8 information, CD-specific antibody levels, pathologic results of duodenal biopsy, treatment received, follow-up status, additional diseases, hormone use, and surgical history was obtained from patient records at PH.In patients diagnosed with PH, a duodenal biopsy was obtained, and the tissue was examined for CD by experienced pathologists. Anti-pituitary antibody (APA) and anti-arginine-vasopressin (AAVP) antibody levels of individuals with PH and CD were measured. RESULTS: The study included 19 patients with lymphocytic hypophysitis, 30 celiac patients, and 30 healthy controls. When patients diagnosed with lymphocytic hypophysitis were examined by duodenal biopsy, no evidence of CD was found in the pathologic findings. The detection rate of HLA-DQ2/8 was 80% in celiac patients and 42% in PH (p=0.044). (APA and AAVP antibodies associated with PH were tested in two separate groups of patients and in the control group. APA and anti-arginine vasopressin (AAVP) levels in PH, CD and healthy controls, respectively M [IQR]: 542 [178-607];164 [125-243]; 82 [74-107] ng/dL (p=0.001), 174 [52-218]; 60 [47-82]; 59 [48-76] ng/dL (p=0.008) were detected. The presence of an HLA-DQ2/8 haplotype correlates with posterior hypophysitis and panhypophysitis (r=0.598, p=0.04 and r=0.657, p=0.02, respectively). CONCLUSION: Although patients with PH were found to have significant levels of HLA-DQ2/8, no CD was found in the tissue. Higher levels of pituitary antibodies were detected in celiac patients compared with healthy controls, but no hypophysitis clinic was observed at follow-up. Although these findings suggest that the two diseases may share a common genetic and autoimmune basis, the development of the disease may be partially explained by exposure to environmental factors.

Vasopressin Receptor Type-2 Mediated Signaling in Renal Cell Carcinoma Stimulates Stromal Fibroblast Activation.

Vasopressin type-2 receptor (V2R) is ectopically expressed and plays a pathogenic role in clear cell renal cell carcinoma (ccRCC) tumor cells. Here we examined how V2R signaling within human ccRCC tumor cells (Caki1 cells) stimulates stromal cancer-associated fibroblasts (CAFs). We found that cell culture conditioned media from Caki1 cells increased activation, migration, and proliferation of fibroblasts in vitro, which was inhibited by V2R gene silencing in Caki1 cells. Analysis of the conditioned media and mRNA of the V2R gene silenced and control Caki1 cells showed that V2R regulates the production of CAF-activating factors. Some of these factors were also found to be regulated by YAP in these Caki1 cells. YAP expression colocalized and correlated with V2R expression in ccRCC tumor tissue. V2R gene silencing or V2R antagonist significantly reduced YAP in Caki1 cells. Moreover, the V2R antagonist reduced YAP expression and myofibroblasts in mouse xenograft tumors. These results suggest that V2R plays an important role in secreting pro-fibrotic factors that stimulate fibroblast activation by a YAP-dependent mechanism in ccRCC tumors. Our results demonstrate a novel role for the V2R-YAP axis in the regulation of myofibroblasts in ccRCC and a potential therapeutic target.

Single-cell transcriptomics of suprachiasmatic nuclei reveal a Prokineticin-driven circadian network.

Circadian rhythms in mammals are governed by the hypothalamic suprachiasmatic nucleus (SCN), in which 20,000 clock cells are connected together into a powerful time-keeping network. In the absence of network-level cellular interactions, the SCN fails as a clock. The topology and specific roles of its distinct cell populations (nodes) that direct network functions are, however, not understood. To characterise its component cells and network structure, we conducted single-cell sequencing of SCN organotypic slices and identified eleven distinct neuronal sub-populations across circadian day and night. We defined neuropeptidergic signalling axes between these nodes, and built neuropeptide-specific network topologies. This revealed their temporal plasticity, being up-regulated in circadian day. Through intersectional genetics and real-time imaging, we interrogated the contribution of the Prok2-ProkR2 neuropeptidergic axis to network-wide time-keeping. We showed that Prok2-ProkR2 signalling acts as a key regulator of SCN period and rhythmicity and contributes to defining the network-level properties that underpin robust circadian co-ordination. These results highlight the diverse and distinct contributions of neuropeptide-modulated communication of temporal information across the SCN.

Maternal Exposure to Dibutyl Phthalate (DBP) or Diethylstilbestrol (DES) Leads to Long-Term Changes in Hypothalamic Gene Expression and Sexual Behavior.

Xenobiotic exposure during pregnancy and lactation has been linked to perinatal changes in male reproductive outcomes and other endocrine parameters. This pilot study wished to assess whether brief maternal exposure of rats to xenobiotics dibutyl phthalate (DBP) or diethylstilbestrol (DES) might also cause long-term changes in hypothalamic gene expression or in reproductive behavior of the resulting offspring. Time-mated female Sprague Dawley rats were given either DBP (500 mg/kg body weight, every second day from GD14.5 to PND6), DES (125 µg/kg body weight at GD14.5 and GD16.5 only), or vehicle (n = 8-12 per group) and mild endocrine disruption was confirmed by monitoring postnatal anogenital distance. Hypothalamic RNA from male and female offspring at PND10, PND24 and PND90 was analyzed by qRT-PCR for expression of aromatase, oxytocin, vasopressin, ER-alpha, ER-beta, kisspeptin, and GnRH genes. Reproductive behavior was monitored in male and female offspring from PND60 to PND90. Particularly, DES treatment led to significant changes in hypothalamic gene expression, which for the oxytocin gene was still evident at PND90, as well as in sexual behavior. In conclusion, maternal xenobiotic exposure may not only alter endocrine systems in offspring but, by impacting on brain development at a critical time, can have long-term effects on male or female sexual behavior.

Central Administration of Angiotensin-(1-7) Improves Vasopressin Impairment and Hypotensive Response in Experimental Endotoxemia.

Angiotensin-(1-7) [Ang-(1-7)]/Mas receptor is a counter-regulatory axis that counteracts detrimental renin-angiotensin system (RAS) effects, especially regarding systemic inflammation, vasopressin (AVP) release, and hypothalamic-pituitary-adrenal (HPA) activation. However, it is not completely understood whether this system may control centrally or systemically the late phase of systemic inflammation. Thus, the aim of this study was to determine whether intracerebroventricular (i.c.v.) administration of Ang-(1-7) can modulate systemic inflammation through the activation of humoral pathways in late phase of endotoxemia. Endotoxemia was induced by systemic injection of lipopolysaccharide (LPS) (1.5 mg/kg, i.v.) in Wistar rats. Ang-(1-7) (0.3 nmol in 2 µL) promoted the release of AVP and attenuated interleukin-6 (IL-6) and nitric oxide (NO) levels but increased interleukin-10 (IL-10) in the serum of the endotoxemic rats. The central administration of Mas receptor antagonist A779 (3 nmol in 2 µL, i.c.v.) abolished these anti-inflammatory effects in endotoxemic rats. Furthermore, Ang-(1-7) applied centrally restored mean arterial blood pressure (MABP) without affecting heart rate (HR) and prevented vascular hyporesponsiveness to norepinephrine (NE) and AVP in animals that received LPS. Together, our results indicate that Ang-(1-7) applied centrally promotes a systemic anti-inflammatory effect through the central Mas receptor and activation of the humoral pathway mediated by AVP.

Vasopressin and copeptin release during sepsis and septic shock.

Sepsis is defined as a potentially fatal organ dysfunction caused by a dysregulated host response to infection. Despite tremendous progress in the medical sciences, sepsis remains one of the leading causes of morbidity and mortality worldwide. The host response to sepsis and septic shock involves changes in the immune, autonomic, and neuroendocrine systems. Regarding neuroendocrine changes, studies show an increase in plasma vasopressin (AVP) concentrations followed by a decline, which may be correlated with septic shock. AVP is a peptide hormone derived from a larger precursor (preprohormone), along with two peptides, neurophysin II and copeptin. AVP is synthesized in the hypothalamus, stored and released from the neurohypophysis into the bloodstream by a wide range of stimuli. The measurement of AVP has limitations due to its plasma instability and short half-life. Copeptin is a more stable peptide than AVP, and its immunoassay is feasible. The blood concentrations of copeptin mirror those of AVP in many physiological states; paradoxically, during sepsis-related organ dysfunction, an uncoupling between copeptin and AVP blood levels appears to happen. In this review, we focus on clinical and experimental studies that analyzed AVP and copeptin blood concentrations over time in sepsis. The findings suggest that AVP and copeptin behave similarly in the early stages of sepsis; however, we did not find a proportional decrease in copeptin concentrations as seen with AVP during septic shock. Copeptin levels were higher in nonsurvivors than in survivors, suggesting that copeptin may work as a marker of severity or sepsis-related organ dysfunction.

Vasopressin in circadian function of SCN.

The suprachiasmatic nucleus (SCN) that acts as the primary circadian pacemaker in mammals is responsible for orchestrating multiple circadian rhythms in every organism. A network structure in the SCN composed of multiple types of neurons orchestrates the circadian rhythms. Despite speculations regarding the working of the clock, the molecular mechanisms governing it is far from clear. The molecular mechanism seems to be woven around the genes present and their linking with the neuromodulators. With the advancement in knowledge regarding the role of neuromodulators in the workings of the clock, especially that of Arginine vasopressin (AVP) and vasoactive intestinal peptide (VIP), the entire picture of the mechanisms involved and therefore the importance of these neuromodulators has changed considerably. AVP seems to be very important for the functioning of the clock and its role has been well established based on the evidence available at present. Enormous research is going on to study the role of AVP and new roles are likely to be assigned to AVP in the execution of function in the SCN. Of late, there have been reports indicating linkage of AVP with jet lag in a positive way, suggesting vasopressin signalling as a possible remedy for ill effects and their improvement. Studies also show circadian rhythm disturbances in mood disorders and the same is related to AVP levels in the SCN. Various findings are thus in accordance with strong suggestions for a critical role for AVP in SCN function.

Role of Oxytocin/Vasopressin-Like Peptide and Its Receptor in Vitellogenesis of Mud Crab.

Oxytocin (OT)/vasopressin (VP) signaling system is important to the regulation of metabolism, osmoregulation, social behaviours, learning, and memory, while the regulatory mechanism on ovarian development is still unclear in invertebrates. In this study, Spot/vp-like and its receptor (Spot/vpr-like) were identified in the mud crab Scylla paramamosain. Spot/vp-like transcripts were mainly expressed in the nervous tissues, midgut, gill, hepatopancreas, and ovary, while Spot/vpr-like were widespread in various tissues including the hepatopancreas, ovary, and hemocytes. In situ hybridisation revealed that Spot/vp-like mRNA was mainly detected in 6-9th clusters in the cerebral ganglion, and oocytes and follicular cells in the ovary, while Spot/vpr-like was found to localise in F-cells in the hepatopancreas and oocytes in the ovary. In vitro experiment showed that the mRNA expression level of Spvg in the hepatopancreas, Spvgr in the ovary, and 17ß-estradiol (E2) content in culture medium were significantly declined with the administration of synthetic SpOT/VP-like peptide. Besides, after the injection of SpOT/VP-like peptide, it led to the significantly reduced expression of Spvg in the hepatopancreas and subduced E2 content in the haemolymph in the crabs. In brief, SpOT/VP signaling system might inhibit vitellogenesis through neuroendocrine and autocrine/paracrine modes, which may be realised by inhibiting the release of E2.

Viral rescue of magnocellular vasopressin cells in adolescent Brattleboro rats ameliorates diabetes insipidus, but not the hypoaroused phenotype.

Dysregulated arousal often accompanies neurodevelopmental disorders such as attention deficit hyperactivity disorder and autism spectrum disorder. Recently, we have found that adolescent homozygous Brattleboro (Hom) rats, which contain a mutation in the arginine vasopressin (AVP) gene, exhibit lower behavioral arousal than their heterozygous (Het) littermates in the open field test. This hypoaroused phenotype could be due to loss of AVP in magnocellular cells that supply AVP to the peripheral circulation and project to limbic structures or parvocellular cells that regulate the stress axis and other central targets. Alternatively, hypoarousal could be a side effect of diabetes insipidus - polydipsia and polyuria seen in Hom rats due to loss of AVP facilitation of water reabsorption in the kidney. We developed a viral-rescue approach to "cure" magnocellular AVP cells of their Brattleboro mutation. Infusion of a recombinant adeno-associated virus (rAAV) containing a functional Avp gene and promoter (rAAV-AVP) rescued AVP within magnocellular cells and fiber projections of the paraventricular nucleus of the hypothalamus (PVN) of male and female adolescent Hom rats. Furthermore, water intake was markedly reduced, ameliorating the symptoms of diabetes insipidus. In contrast, open field activity was unaffected. These findings indicate that the hyporaoused phenotype of adolescent Hom rats is not due to the loss of AVP function in magnocellular cells or a side effect of diabetes insipidus, but favors the hypothesis that central, parvocellular AVP mechanisms underlie the regulation of arousal during adolescence.

The Novel Ser18del AVP Variant Causes Inherited Neurohypophyseal Diabetes Insipidus by Mechanisms Shared with Other Signal Peptide Variants.

BACKGROUND/AIM: Variability in the severity and age at onset of autosomal dominant familial neurohypophyseal diabetes insipidus (adFNDI) may be associated with certain types of variants in the arginine vasopressin (AVP) gene. In this study, we aimed to describe a large family with an apparent predominant female occurrence of polyuria and polydipsia and to determine the underlying cause. METHODS: The family members reported their family demography and symptoms. Two subjects were diagnosed by fluid deprivation and dDAVP challenge tests. Eight subjects were tested genetically. The identified variant along with 3 previously identified variants in the AVP gene were investigated by heterologous expression in a human neuronal cell line (SH-SY5Y). RESULTS: Both subjects investigated clinically had a partial neurohypophyseal diabetes insipidus phenotype. A g.276_278delTCC variant in the AVP gene causing a Ser18del deletion in the signal peptide (SP) of the AVP preprohormone was perfectly co-segregating with the disease. When expressed in SH-SY5Y cells, the Ser18del variant along with 3 other SP variants (g.227G>A, Ser17Phe, and Ala19Thr) resulted in reduced AVP mRNA, impaired AVP secretion, and partial AVP prohormone degradation and retention in the endoplasmic reticulum. Impaired SP cleavage was demonstrated directly in cells expressing the Ser18del, g.227G>A, and Ala19Thr variants, using state-of-the-art mass spectrometry. CONCLUSION: Variants affecting the SP of the AVP preprohormone cause adFNDI with variable phenotypes by a mechanism that may involve impaired SP cleavage combined with effects at the mRNA, protein, and cellular level.

Genetic variant repressing ADH1A expression confers susceptibility to esophageal squamous-cell carcinoma.

Genome-wide association studies (GWAS) have discovered numerous genetic susceptibility loci including a cluster of alcohol dehydrogenase (ADH) gene family for esophageal squamous-cell carcinoma (ESCC). However, the underlying mechanism has not fully been elucidated. In this study, we integrated the GWAS data, gene-drinking interaction, expression quantitative trait locus (eQTL) analysis and biochemical experiments to clarify the specific mechanism of the polymorphisms in ADH loci. By imputation and eQTL analysis, we identified rs1154402C>G in intron 1 of ADH5 substantially associated with the expression levels of ADH1A. Association analysis showed that the rs1154402[G] allele was significantly associated with ESCC risk in drinkers (OR = 1.44, 95% CI = 1.20-1.73; P = 7.74 × 10-5) but not in nondrinkers (OR = 1.14, 95% CI = 0.93-1.37; P = .220). Furthermore, the ADH5 variant showed a significant interaction with drinking and the genetic variant near ALDH2 encoding the enzyme oxidizing acetaldehyde, a carcinogenic product resulted from alcohol oxidation catalyzed by ADHs. We demonstrated for the first time that rs1154402C>G change might create a silencer, repressing ADH1A transcription via long-range interaction with ADH1A promoter. These results suggest that genetic variant in ADH5 might confer alcohol drinkers susceptible to ESCC by down-regulation of ADH1A, which weakens alcohol catabolism.

Impaired AQP2 trafficking in Fxyd1 knockout mice: A role for FXYD1 in regulated vesicular transport.

The final adjustment of urine volume occurs in the inner medullary collecting duct (IMCD), chiefly mediated by the water channel aquaporin 2 (AQP2). With vasopressin stimulation, AQP2 accumulation in the apical plasma membrane of principal cells allows water reabsorption from the lumen. We report that FXYD1 (phospholemman), better known as a regulator of Na,K-ATPase, has a role in AQP2 trafficking. Daytime urine of Fxyd1 knockout mice was more dilute than WT despite similar serum vasopressin, but both genotypes could concentrate urine during water deprivation. FXYD1 was found in IMCD. In WT mice, phosphorylated FXYD1 was detected intracellularly, and vasopressin induced its dephosphorylation. We tested the hypothesis that the dilute urine in knockouts was caused by alteration of AQP2 trafficking. In WT mice at baseline, FXYD1 and AQP2 were not strongly co-localized, but elevation of vasopressin produced translocation of both FXYD1 and AQP2 to the apical plasma membrane. In kidney slices, baseline AQP2 distribution was more scattered in the Fxyd1 knockout than in WT. Apical recruitment of AQP2 occurred in vasopressin-treated Fxyd1 knockout slices, but upon vasopressin washout, there was more rapid reversal of apical AQP2 localization and more heterogeneous cytoplasmic distribution of AQP2. Notably, in sucrose gradients, AQP2 was present in a detergent-resistant membrane domain that had lower sedimentation density in the knockout than in WT, and vasopressin treatment normalized its density. We propose that FXYD1 plays a role in regulating AQP2 retention in apical membrane, and that this involves transfers between raft-like membrane domains in endosomes and plasma membranes.

ER-associated degradation is required for vasopressin prohormone processing and systemic water homeostasis.

Peptide hormones are crucial regulators of many aspects of human physiology. Mutations that alter these signaling peptides are associated with physiological imbalances that underlie diseases. However, the conformational maturation of peptide hormone precursors (prohormones) in the ER remains largely unexplored. Here, we report that conformational maturation of proAVP, the precursor for the antidiuretic hormone arginine-vasopressin, within the ER requires the ER-associated degradation (ERAD) activity of the Sel1L-Hrd1 protein complex. Serum hyperosmolality induces expression of both ERAD components and proAVP in AVP-producing neurons. Mice with global or AVP neuron-specific ablation of Se1L-Hrd1 ERAD progressively developed polyuria and polydipsia, characteristics of diabetes insipidus. Mechanistically, we found that ERAD deficiency causes marked ER retention and aggregation of a large proportion of all proAVP protein. Further, we show that proAVP is an endogenous substrate of Sel1L-Hrd1 ERAD. The inability to clear misfolded proAVP with highly reactive cysteine thiols in the absence of Sel1L-Hrd1 ERAD causes proAVP to accumulate and participate in inappropriate intermolecular disulfide-bonded aggregates, promoted by the enzymatic activity of protein disulfide isomerase (PDI). This study highlights a pathway linking ERAD to prohormone conformational maturation in neuroendocrine cells, expanding the role of ERAD in providing a conducive ER environment for nascent proteins to reach proper conformation.

[Small cell lung cancer associated with multiple paraneoplastic syndromes].

We report the case of a patient presenting with multiple severe electrolyte disturbances who was subsequently found to have small cell lung cancer. Upon further evaluation, she demonstrated three distinct paraneoplastic processes, including the syndrome of inappropriate antidiuretic hormone, Fanconi syndrome, and an inappropriate elevation in fibroblast growth factor-23 (FGF23). The patient underwent one round of chemotherapy, but she was found to have progressive disease. After 36 days of hospitalization, the patient made the decision to enter hospice care and later she expired.

Adipsic diabetes insipidus in adult patients.

INTRODUCTION: Adipsic diabetes insipidus (ADI) is a very rare disorder, characterized by hypotonic polyuria due to arginine vasopressin (AVP) deficiency and failure to generate the sensation of thirst in response to hypernatraemia. As the sensation of thirst is the key homeostatic mechanism that prevents hypernatraemic dehydration in patients with untreated diabetes insipidus (DI), adipsia leads to failure to respond to aquaresis with appropriate fluid intake. This predisposes to the development of significant hypernatraemia, which is the typical biochemical manifestation of adipsic DI. METHODS: A literature search was performed to review the background, etiology, management and associated complications of this rare condition. RESULTS: ADI has been reported to occur in association with clipping of an anterior communicating artery aneurysm following subarachnoid haemorrhage, major hypothalamic surgery, traumatic brain injury and toluene exposure among other conditions. Management is very difficult and patients are prone to marked changes in plasma sodium concentration, in particular to the development of severe hypernatraemia. Associated hypothalamic disorders, such as severe obesity, sleep apnoea and thermoregulatory disorders are often observed in patients with ADI. CONCLUSION: The management of ADI is challenging and is associated with significant morbidity and mortality. Prognosis is variable; hypothalamic complications lead to early death in some patients, but recent reports highlight the possibility of recovery of thirst.

Small cell lung cancer associated with multiple paraneoplastic syndromes / Cáncer de pulmón de células pequeñas asociado a múltiples síndromes paraneoplásicos

Abstracts We report the case of a patient presenting with multiple severe electrolyte disturbances who was subsequently found to have small cell lung cancer. Upon further evaluation, she demonstrated three distinct paraneoplastic processes, including the syndrome of inappropriate antidiuretic hormone, Fanconi syndrome, and an inappropriate elevation in fibroblast growth factor-23 (FGF23). The patient underwent one round of chemotherapy, but she was found to have progressive disease. After 36 days of hospitalization, the patient made the decision to enter hospice care and later she expired.

Resumen Se reporta el caso de una paciente que ingresó al hospital para evaluación de múltiples trastornos electrolíticos y, posteriormente, se le hizo el diagnóstico de cáncer de pulmón de células pequeñas. Tras la evaluación médica, se detectaron tres síndromes paraneoplásicos: síndrome de secreción inadecuada de hormona antidiurética, síndrome de Fanconi y elevación inapropiada del factor 23 de crecimiento de fibroblastos. Se le administró quimioterapia sin éxito, por lo cual se decidió darle tratamiento paliativo y, un tiempo después, falleció.

The Impact of Oxytocin Gene Knockout on Sexual Behavior and Gene Expression Related to Neuroendocrine Systems in the Brain of Female Mice.

Social relations are built and maintained from the interaction among individuals. The oxytocin (OT), vasopressin (VP), estrogen, dopamine, and their receptors are involved in the modulation of sexual behavior in females. This study aimed to analyze the impact of OT gene knockout (OTKO) on sexual behavior and the gene expression of oxytocin (OTR), estrogen alpha (ERα), estrogen beta (ERß), vasopressin (V1aR), and dopamine (D2R) receptors in the olfactory bulb (OB), prefrontal cortex (PFC), hippocampus (HPC), and hypothalamus (HPT), as well as in the synthesis of VP in the HPT of female mice. Wild-type (WT) littermates were used for comparisons. The CDNAs were synthesized by polymerase chain reaction and the gene expression was calculated with the 2-ΔΔCt formula. Our results showed that the absence of OT caused an increase in the frequency and duration of non-receptive postures and a decrease in receptive postures in the OTKO. OTKO females showed a significant decrease in the gene expression of OTR in the HPC, V1aR in the HPT, and ERα and ERß in the PFC. There was no significant difference in the gene expression of D2R of OTKO. However, OTKO showed an increased gene expression of V1aR in the HPC. There is no significant difference in VP mRNA synthesis in the HPT between OTKO and WT. Our findings demonstrate that the absence of OT leads to significant changes in the expression of the studied genes (OTR, ERα, ERß, V1aR), and these changes may contribute to the decreased sexual behavior observed in OTKO females.

Demonstration of the functional impact of vasopressin signaling in the thick ascending limb by a targeted transgenic rat approach.

The antidiuretic hormone vasopressin (AVP) regulates renal salt and water reabsorption along the distal nephron and collecting duct system. These effects are mediated by vasopressin 2 receptors (V2R) and release of intracellular Gs-mediated cAMP to activate epithelial transport proteins. Inactivating mutations in the V2R gene lead to the X-linked form of nephrogenic diabetes insipidus (NDI), which has chiefly been related with impaired aquaporin 2-mediated water reabsorption in the collecting ducts. Previous work also suggested the AVP-V2R-mediated activation of Na(+)-K(+)-2Cl(-)-cotransporters (NKCC2) along the thick ascending limb (TAL) in the context of urine concentration, but its individual contribution to NDI or, more generally, to overall renal function was unclear. We hypothesized that V2R-mediated effects in TAL essentially determine its reabsorptive function. To test this, we reevaluated V2R expression. Basolateral membranes of medullary and cortical TAL were clearly stained, whereas cells of the macula densa were unreactive. A dominant-negative, NDI-causing truncated V2R mutant (Ni3-Glu242stop) was then introduced into the rat genome under control of the Tamm-Horsfall protein promoter to cause a tissue-specific AVP-signaling defect exclusively in TAL. Resulting Ni3-V2R transgenic rats revealed decreased basolateral but increased intracellular V2R signal in TAL epithelia, suggesting impaired trafficking of the receptor. Rats displayed significant baseline polyuria, failure to concentrate the urine in response to water deprivation, and hypercalciuria. NKCC2 abundance, phosphorylation, and surface expression were markedly decreased. In summary, these data indicate that suppression of AVP-V2R signaling in TAL causes major impairment in renal fluid and electrolyte handling. Our results may have clinical implications.

Depressive- and anxiety-like behaviors and stress-related neuronal activation in vasopressin-deficient female Brattleboro rats.

Vasopressin can contribute to the development of stress-related psychiatric disorders, anxiety and depression. Although these disturbances are more common in females, most of the preclinical studies have been done in males. We compared female vasopressin-deficient and +/+ Brattleboro rats. To test anxiety we used open-field, elevated plus maze (EPM), marble burying, novelty-induced hypophagia, and social avoidance tests. Object and social recognition were used to assess short term memory. To test depression-like behavior consumption of sweet solutions (sucrose and saccharin) and forced swim test (FST) were studied. The stress-hormone levels were followed by radioimmunoassay and underlying brain areas were studied by c-Fos immunohistochemistry. In the EPM the vasopressin-deficient females showed more entries towards the open arms and less stretch attend posture, drank more sweet fluids and struggled more (in FST) than the +/+ rats. The EPM-induced stress-hormone elevations were smaller in vasopressin-deficient females without basal as well as open-field and FST-induced genotype-differences. On most studied brain areas the resting c-Fos levels were higher in vasopressin-deficient rats, but the FST-induced elevations were smaller than in the +/+ ones. Similarly to males, female vasopressin-deficient animals presented diminished depression- and partly anxiety-like behavior with significant contribution of stress-hormones. In contrast to males, vasopressin deficiency in females had no effect on object and social memory, and stressor-induced c-Fos elevations were diminished only in females. Thus, vasopressin has similar effect on anxiety- and depression-like behavior in males and females, while only in females behavioral alterations are associated with reduced neuronal reactivity in several brain areas.