Reproductive performance and progeny sex ratio of female Chukar (Alectoris chukar) breeder partridges reared on restricted feeding regimens.

A hypothesis was tested that quantitative feed restriction affects the reproductive performance and offspring sex ratio of female Chukar breeder partridges. A total of 160 2.5-year-old male and female partridges were randomly allotted to four treatment groups. The birds in the control group were fed ad libitum, whereas those in treatments G95 , G90 , and G85 received 26.1, 24.7, and 23.3 g of feed per bird/day to provide 95%, 90%, and 85% of ad libitum feeding level, respectively. The reproductive performances of female Chukar partridges including egg production, egg quality, fertility rate, duration of fertility, hatchability, chick quality, mortality rate, and offspring sex ratio (using a PCR procedure) were investigated. Feed restriction of all levels decreased the body weight and egg production compared with the ad libitum birds; however, restricted feeding had no significant effect on the egg quality traits. Non-significant effects of treatment on fertility and hatchability rate were found. The restricted feeding reduced the duration of fertility. Furthermore, maternal restricted feeding resulted in decreased chick weights. The results of this study showed that embryonic mortality was not affected by the restricted feeding of Chukar breeder partridges. Interestingly, restricted feeding was associated with a decreased proportion of male offspring. Overall, body weight, egg production, duration of fertility, progeny chick weight, and sex ratio were responsive to restricted feeding where their changes make the restricted feeding regimens to not be practically recommended in breeder partridge production. These results are in contrast to the conventional restricted feeding program implemented in broiler breeder industry.

Comparative Meta-analysis of Adipose Tissue Transcriptomics Data in PCOS Patients and Healthy Control Women.

Polycystic ovary syndrome (PCOS) is a common condition in reproductive-aged women that induces reproductive and metabolic derangements. Women with PCOS seem to have disturbances in lipid metabolism in the adipose tissue. Nevertheless, gene expression in adipose tissue of PCOS women and its relation to other disturbances have been fragmentarily investigated. We utilized microarray data to identify the most important up- and down-regulated candidate genes in adipose tissue of PCOS women in contrast to healthy women using the meta-analysis technique. Microarray data produced from three independent experiments (n = 3) conducted on adipose tissue in women with PCOS were retrieved from ArrayExpress. Then, the datasets were merged using the metaSeq package in Rstudio and differentially expressed genes (DEGs) were selected in the studies. The integrative bioinformatics analyses of candidate genes were performed by gene ontology (GO) analysis, Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis, and protein-protein interaction (PPI) network construction. Of these, 12 up-regulated genes and 12 down-regulated genes were identified and assessed as the most highly up-regulated and down-regulated genes in adipose tissue of women with PCOS. These DEGs that were annotated by KEGG analysis were mainly involved in PI3K-Akt, MAPK, Rap1, and Ras signaling pathways, and pathways in cancer such as hepatocellular carcinoma and gastric cancer, as well as metabolic pathways, and brain disorder pathways such as Alzheimer's disease and Huntington disease pathways. In the PPI networks, PRDM10, FGFR2, IGF1R, and FLT1 were the key nodes in the up-regulated networks, while the NDUFAB1 and NME2 proteins were key in the down-regulated networks. Overall, these findings provide insight into the gene expression in adipose tissue of PCOS women and its relation to other disturbances.

Maternal aromatase inhibition via letrozole altered RFamide-related peptide-3 and gonadotropin-releasing hormone expression in pubertal female rats.

Objectives: Despite prevalence of polycystic ovary syndrome (PCOS) among childbearing women and development of many animal models for this syndrome, information on its etiology is still scarce. The intrauterine hyperandrogenic environment may underlie changes at the level of hypothalamus, pituitary, ovary organization in female offspring, and PCOS later in life. Letrozole has been shown to mimic reproductive and metabolic characteristics of PCOS in adult rodent models. Therefore, this research aimed to assess the condition in a prenatal letrozole-treated rat model. Materials and Methods: Twenty-eight female rats dams receiving letrozole at certain doses during late pregnancy were used in the trial. Pregnant Sprague-Dawley rats (n=21) received letrozole treatment on gestation days 16-18 at doses of 1.25, 1.0, 0.75, 0.5, and 0.25 mg/kg body weight (BW). Results: Prenatal letrozole treatment delayed parturition time and reduced the litter size in pregnant dams (P<0.0001). Late puberty onset, irregular ovarian cyclicity, increased anogenital distance (AGD), body weight gain, serum testosterone concentration, and reduced estradiol levels (P<0.0001) were observed in the female offspring of dams receiving 1.25 and 1 mg/kg BW letrozole. Furthermore, letrozole at 1.25 and 1 mg/kg BW showed increased RFRP and decreased GnRH mRNA expression (P<0.0001). Letrozole treatment at doses of 1 mg/kg BW and lower was not fetotoxic. Conclusion: It was concluded that 1 mg/kg BW letrozole may be suggested for prenatal PCOS induction.

Reproductive complications after stroke: Long-lasting impairment of gonadotropin-releasing hormone neuronal network?

Some studies have demonstrated that stroke may increase the risk of pregnancy complications and early menopause. In addition, preclinical investigations revealed the middle cerebral artery occlusion could affect hypothalamus. Since hypothalamus is the core of central circuits regulating reproductive processes, impairment of hypothalamic gonadotropin-releasing hormone neuronal network following stroke might be manifested in long-lasting reproductive disorders.

Pathophysiologic Mechanisms of Insulin Secretion and Signaling-Related Genes in Etiology of Polycystic Ovary Syndrome.

Polycystic ovary syndrome (PCOS) is a common endocrinopathy in women. PCOS is characterized by anovulation, hyperandrogenism, polycystic ovaries, insulin resistance, and obesity. Despite the finding that the genetic origin of PCOS is well demonstrated in previous twin and familial clustering studies, genes and factors that can exactly explain the PCOS pathophysiology are not known. Objective(s). In this review, we attempted to identify genes related to secretion and signaling of insulin aspects of PCOS and their physiological functions in order to explain the pathways that are regulated by these genes which can be a prominent function in PCOS predisposition. Materials and Methods. For this purpose, published articles and reviews dealing with genetic evaluation of PCOS in women from peer-reviewed journals in PubMed and Google Scholar databases were included in this review. Results. The genomic investigations in women of different populations identified many candidate genes and loci that are associated with PCOS. The most important of them are INSR, IRS1-2, MTNR1A, MTNR1B, THADA, PPAR-γ2, ADIPOQ, and CAPN10. These are mainly associated with metabolic aspects of PCOS. Conclusions. In this review, we proposed that each of these genes may interrupt specific physiological pathways by affecting them and contribute to PCOS initiation. It is clear that the role of genes involved in insulin secretion and signaling is more critical than other pathways.

Male subfertility effects of sub-chronic ethanol exposure during stress in a rat model.

BACKGROUND: Stressful conditions increase alcohol consumption in men. Clinical studies link disruption of the neuroendocrine stress system with alcoholism, but the effect of alcohol in a stress condition on male fertility is still relatively poorly understood. This project was undertaken to evaluate the effect of sub-chronic alcohol in a stress condition on male fertility in a rat model. METHODS: Male Sprague-Dawley rats were randomly divided into a control group, a stress group that was exposed to restraint stress, an ethanol group that was injected with ethanol daily, and a stress + ethanol group that was injected with ethanol daily and was exposed to restraint stress, simultaneously. Furthermore, testis tissue was evaluated histomorphometrically and immunohistochemically for apoptosis using a TUNEL assay after 12 days. Epididymis sperm analysis was done. Blood cortisol and testosterone were measured and expression of hypothalamic kisspeptin (Kiss1), RFRP-3, and MC4R mRNA were evaluated. RESULTS: Ethanol exposure during restraint stress did not alter body weight. Ethanol exposure decreased the cellular diameter and area, and stress increased the cellular diameter and area, in comparison with the control group. In the stress group, in comparison with the other groups, the number of seminiferous tubules decreased and the numerical density of seminiferous tubules increased. In addition, ethanol exposure and/or stress reduced semen analysis parameters (sperm viability and motility), but did not change serum testosterone concentrations. Apoptosis increased in spermatogonia with ethanol exposure, but spermatocytes were not affected. Our data present the novel finding that ethanol and stress reduced hypothalamic Kiss1 mRNA expression, while ethanol exposure decreased hypothalamic RFRP-3 and MC4R mRNA expression. CONCLUSIONS: Ethanol decreased cortisol hormone level during the restraint stress condition and attenuated hypothalamic reproductive-related gene expressions. Therefore, ethanol exposure may induce reduction of sperm viability, increased sperm mortality, and increased apoptosis, with long-term effects, and may induce permanent male subfertility.

Three-dimensional and two-dimensional relationships of gangliogenesis with folliculogenesis in mature mouse ovary: a Golgi-Cox staining approach.

The present study was set out to investigate two-dimensional (2D) and three-dimensional (3D) evaluations of ovarian nervous network development and the structural relationship between folliculogenesis and gangliogenesis in mouse ovaries. Adult mice ovarian tissue samples were collected from follicular and luteal phases after cardiac perfusion. Ovarian samples were stained by a Golgi-Cox protocol. Following staining, tissues were serially sectioned for imaging. Neural filaments and ganglia were present in the ovaries. In both 2D and 3D studies, an increase in the number and area of ganglia was seen during the follicular growth. The same pattern was also seen in corpora lutea development. However, in some cases such as ratio of ganglia number to follicle area, the ratio of ganglia area to follicular area, 2D findings were different compared with the 3D results. 3D analysis of ovarian gangliogenesis showed the possible direct effect of them on folliculogenesis. Golgi-Cox staining was used in this study for 3D evaluation in non-brain tissue. The results of 3D analysis of the present study showed that, in some cases, the information provided by 2D analysis does not match the reality of ovarian neuronal function. This confirmed the importance of 3D analysis for evaluation of ovarian function.

Prepubertal exposure to high dose of cadmium induces hypothalamic injury through transcriptome profiling alteration and neuronal degeneration in female rats.

Cadmium (Cd) is a toxic metal, which seems to be crucial during the prepubertal period. Cd can destroy the structural integrity of the blood-brain barrier (BBB) and enters into the brain. Although the brain is susceptible to neurotoxicity induced by Cd, the effects of Cd on the brain, particularly hypothalamic transcriptome, are still relatively poorly understood. Therefore, we investigated the molecular effects of Cd exposure on the hypothalamus by profiling the transcriptomic response of the hypothalamus to high dose of Cd (25 mg/kg bw/day cadmium chloride (CdCl2)) during the prepubertal period in Sprague-Dawley female rats. After sequencing and annotation, differential expression analysis revealed 1656 genes that were differentially expressed that 108 of them were classified into 37 transcription factor (TF) families. According to gene ontology (GO) annotation and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis, these differentially expressed genes (DEGs) were involved in different biological processes and neurological disorders including Alzheimer's disease (AD), Huntington's disease (HD), and Parkinson's disease (PD), prolactin signaling pathway, PI3K/Akt signaling, and dopaminergic synapse. Five transcripts were selected for further analyses with Real-time quantitative PCR (RT-qPCR). The RT-qPCR results were mostly consistent with those from the high throughput RNA sequencing (RNA-seq). Cresyl violet staining clearly showed an increased neuronal degeneration in the dorsomedial hypothalamus (DMH) and arcuate (Arc) nuclei of the CdCl2 group. Overall, this study demonstrates that prepubertal exposure to high doses of Cd induces hypothalamic injury through transcriptome profiling alteration in female rats, which reveals the new mechanisms of pathogenesis of Cd in the hypothalamus.

Detrimental effects of long-term exposure to heavy metals on histology, size and trace elements of testes and sperm parameters in Kermani Sheep.

Exposure to endocrine-disrupting chemicals (EDCs) has been hypothesized as a cause of declining sheep reproductive efficiency. Understanding the long-term effects of EDCs such as heavy metals on reproductive health requires investigation in 'real life' of sheep that are reared in industrial areas. The aim of this study was to evaluate the effect of long-term exposure of Kermani rams to high levels of environmental heavy metals probably emitted from a copper smelter at KhatoonAbad in ShahreBabak, Kerman province. Testicular characteristics were determined in randomly-selected rams (3-4 years old) at 4 directions (south, north, east, and west) and 4 distances (10, 20, 30, and 40 km) from the smelter. Testicular trace element contents, size, serum testosterone, histological attributes and seminal characteristics, except semen volume, were affected by both the direction and the distance from the smelter (P < 0.05). Testicular contents of Pb, Cd, Cr, and Ni, and sperm abnormalities were higher at 10 km south from the smelter and lower at 40 km west. Other parameters were higher at 40 km west and lower at 10 km south. Interestingly, the testicular contents of Cu at 10 km south were lower and associated with higher sperm abnormalities in the rams reared closer to the smelter. The highest weight, length and circumference of the testis were found at 40 km west. The lowest concentration of testosterone was observed at 10 km south, being 92.6% lower than the highest values obtained at 40 km west. The diameter of seminiferous tubules and epithelial height at 10 km south were 8.9% and 27.5% lower than the highest values obtained at 40 km west. A positive correlation between Pb, Cd, Cr and Ni contents in the testis with sperm abnormalities, and a negative correlation between these elements with the other parameters were found. It was concluded that long-term exposure to heavy metals might have been a cause of decreased fertility in rams and probably other living species in this region.

Effect of Prepubertal Exposure to CdCl2 on the Liver, Hematological, and Biochemical Parameters in Female Rats; an Experimental Study.

The examination chemical factors including industrial toxins and heavy metals seem to be crucial during the prepubertal period. In order to investigate the effects of prepubertal exposure to toxic doses of Cd on liver, hematological, and biochemical parameters in the serum, 16 female rats weaned on postnatal day (PND) 21 were randomly divided into four groups with four rats in each (n = 4). The treatments were as follows: control (0.5 mL distilled water), 25, 50, and 75 mg/kg/day received cadmium chloride (CdCl2). The CdCl2 were administered orally from PND 21 days until observed first vaginal opening (VO). The result showed that the treatment of 75 mg/kg CdCl2 dramatically increased the serum level of LDL (P < 0.0001) and LDL/HDL ratio (P = 0.0004). Conversely, treatment of 75 mg/kg CdCl2 considerably decreased the serum level of HDL in comparison with control group (P = 0.0002). Nevertheless, the rats that received different doses of CdCl2 showed no significant differences in Glu, TG, and TC compared to control group. Number of RBC and Hb of rats treated with 75 mg/kg CdCl2 were significantly less than the other groups (P < 0.0001), whereas a number of WBCs in rats treated with 75 mg/kg CdCl2 (5.27 ± 0.13 103/µL) showed significant difference (P < 0.0001) compared to control group (4.23 ± 0.09 103/µL). Histopathological exams showed nodular accumulation of lymphocytes in the liver (lymphocytic hepatitis) of rats, treated with 75 mg/kg CdCl2. These results showed that CdCl2 could cause change in serum lipidome and hematological parameters. What is more, exposure to Cd triggers liver injury and cardiovascular disease during the prepubertal period.

Pathophysiological mechanisms of gonadotropins- and steroid hormones-related genes in etiology of polycystic ovary syndrome.

OBJECTIVES: Polycystic ovary syndrome (PCOS) is an endocrinopathy in women, which, unlike its impact on fertility and health of women, there is no clear understanding about the causal mechanisms of this pathogenesis. The aim of this review paper is to investigate the pathophysiological pathways affecting the PCOS etiology, based on functions of gonadotropins- and steroid hormones-related genes. MATERIALS AND METHODS: Due to different hormonal and metabolic signs of this complex disorder, different hypotheses are mentioned about etiology of this syndrome. Because of the heterogeneity of the reasons given for this syndrome and the spread of the effective genes in its pathophysiology, most of genes affected by sex-related hormonal imbalances are examined for discriminative diagnosis. For this purpose, published articles and reviews dealing with genetic evaluation of PCOS in women in peer-reviewed journals in PubMed and Google Scholar databases were included in this review. RESULTS: In previous studies, it has been well demonstrated that PCOS in some individuals have a genetic origin. Pathophysiological functions of genes are primarily responsible for the synthesis of proteins that have role in PCOS before hyperandrogenism including GnRHR, FSHß, FSHR, LHCGR, CYP19A1, HSD17B, AR and SHBG, and their effects in PCOS of human have been confirmed. CONCLUSION: Hormonal imbalances are the first reason mentioned in PCOS etiology, and usually characterized with menstrual irregularities in PCOS women. Hyperandrogenism and gonadotropin secretion disorders are shown in PCOS condition, which are related to steroidogenesis pathways and hypothalamic-pituitary-ovarian axis disturbances, respectively.

Pathophysiologic mechanisms of obesity- and chronic inflammation-related genes in etiology of polycystic ovary syndrome.

OBJECTIVES: One of the common heterogeneous reproductive disorders in women of childbearing age is polycystic ovary syndrome (PCOS). It is characterized by lack of fertility due to anovulatory cycles, hyperandrogenemia, polycystic ovaries, hyperinsulinemia, and obesity. Both reproductive anomalies and metabolic disorders are involved in PCOS pathology. Although the role of increased levels of androgens in initiation of PCOS is almost proven, mechanisms of PCOS pathophysiology are not clear. Here we discuss roles of altered metabolic conditions, obesity, and chronic inflammation in PCOS pathophysiology. MATERIALS AND METHODS: In this review, we attempted to identify genes related to obesity and chronic inflammation aspects of PCOS and their physiological functions to explain the pathways that are regulated by these genes and can be a prominent function in PCOS predisposition. For this purpose, published articles and reviews dealing with genetic evaluation of PCOS in women in peer-reviewed journals in PubMed and Google Scholar databases were included in this review. RESULTS: Obesity and chronic inflammation are not prominent diagnostic features of PCOS, but they play an important role in exacerbating metabolic and hyperandrogenic states. ADIPOQ, FTO TGFß, and DENND1A as the main obesity- and chronic inflammation-related genes have roles in PCOS pathophysiology. CONCLUSION: It seems that genes related to obesity pathology in genomic research association, are related to metabolic aspects and body mass index in PCOS patients. Genomes have roles in chronic inflammation, followed by obesity, in the pathogenesis of PCOS.

Fast free of acrylamide clearing tissue (FACT) for clearing, immunolabelling and three-dimensional imaging of partridge tissues.

Fast free of acrylamide clearing tissue (FACT) is a modified sodium dodecyl sulfate-based clearing protocol for the chemical clearing of lipids that completely preserves fluorescent signals in the cleared tissues. The FACT protocol was optimized to image translucent immunostained brain and non-nervous tissues. For this purpose adult male Chukar partridge (Alectoris chukar) was used as a model. After clearing the tissues, 1 or 2 mm-thickness sections of tissues were immunolabeled. The paraventricular nucleus in the hypothalamus (2-mm section) was cleared with FACT, and then was stained with gonadotropin-inhibitory hormone (GnIH) antibody and Hoechst. Simultaneously, immunohistochemical (IHC) staining of cryosectioned brain (30 µm) was done by GnIH-antibody. The FACT protocol and staining of cell nuclei of nine other tissues were done by a z-stack motorized fluorescent microscope. GnIH-immunoreactive neurons were found by FACT and IHC during the breeding season in male partridges. Deep imaging of the kidney, duodenum, jejunum, lung, pancreas, esophagus, skeletal muscle, trachea, and testis were also done. The FACT protocol can be used for the three-dimensional imaging of various tissues and immunostained evaluation of protein markers. RESEARCH HIGHLIGHT: The FACT is a simple and cheap method for whole tissue clearing. The FACT-cleared tissues can be imaged with simple fluorescent microscopes. For the first time, using the FACT, three-dimensional imaging of various tissues was done.

Decreased Expression of Arginine-Phenylalanine-Amide-Related Peptide-3 Gene in Dorsomedial Hypothalamic Nucleus of Constant Light Exposure Model of Polycystic Ovarian Syndrome.

BACKGROUND: An abnormality in pulse amplitude and frequency of gonadotropin releasing hormone (GnRH) secretion is the most characteristics of polycystic ovarian syndrome (PCOS). On the other hand, arginine-phenylalanine-amide (RFamide)-related peptide-3 (RFRP3) inhibits the secretion of GnRH in mammalian hypothalamus. The current study performed in order to investigate the expression of RFRP3 mRNA in the dorsomedial hypothalamic nucleus (DMH) after the induction of PCOS in a rat model of constant light exposure, and the possible role of parity on occurrence of PCOS. MATERIALS AND METHODS: In the experimental study, female nulliparous (n=12) and primiparous (n=12) rats were randomly subdivided into control and PCOS subgroups (n=6). PCOS were induced by 90 days exposure to constant light. After 90 days, blood, brain, and ovaries were sampled. Serum levels of follicle stimulating hormone (FSH), luteinizing hormone (LH), and testosterone were evaluated. In addition, six adult female ovariectomized rats as a control of real-time polymerase chain reaction (PCR) tests were prepared and in the DMH of all rats, the relative mRNA expression of RFRP3 was assessed. RESULTS: Histological evaluation of ovaries represented the polycystic features. In addition, serum concentrations of testosterone in the PCOS subgroups were more than the controls (P<0.05). Furthermore, the relative expression of RFRP3 mRNA in PCOS subgroups was lower than the controls (P<0.05). CONCLUSION: Constant light model of the PCOS-induced rats decreased the gene expression of RFRP3 in the DMH that suggests the decrease of RFRP3 may reduce its inhibitory effect on GnRH during the PCOS pathogenesis. This effect was stronger in the nulliparous rats than the primiparous.

Enhancement of Melanocortin-4 Receptor (MC4R) and Constancy of Kiss1 mRNAs Expression in the Hypothalamic Arcuate Nucleus in a Model of Polycystic Ovary Syndrome Rat.

BACKGROUND: Hypothalamic Melanocortin-4 Receptor (MC4R) and kiss1/kisspeptin systems play roles in reproductive processes. This study was conducted to evaluate changes in MC4R and kiss1 genes expression in the arcuate nucleus (ARC) of the hypothalamus and its relationship with polycystic ovary syndrome (PCOS) in rats. MATERIALS AND METHODS: In the current experimental study, 24 female rats were randomly and equally allocated into nulliparous and primiparous groups and then were divided into two subgroups of PCOS and control. PCOS was induced by exposure to continuous light. Sex-related hormones were evaluated by radioimmunoassay or immunoradiometric assay. Expressions of MC4R and kiss1 gene in the ARC of the hypothalamus of the rats were evaluated by real-time PCR. Histomorphometric alterations of ovaries were compared between groups. RESULTS: Number of tertiary follicles and their size and number of atretic follicles in the PCOS subgroups were more than those in the controls (P<0.05) whereas the number of secondary follicles and corpus luteum in the PCOS subgroups were lower than those in the controls (P<0.05). Antrum and total diameters of tertiary follicles in the PCOS subgroups were greater and granulosa layer diameter was lower than those in the controls (P<0.05). The MC4R mRNA expression in the PCOS subgroups was 6.5-fold in nulliparous and 3.5-fold in primiparous groups more than their controls' pairs (P<0.05). However, parity did not affect the expression of MC4R gene (P>0.05). The kiss1 mRNA expression in the PCOS and control subgroups was not significantly different (P>0.05). CONCLUSION: Overexpression of MC4R gene after PCOS induction in the ARC of the hypothalamus may link to metabolic disorders of induced PCOS in the rats. However, alteration in the kiss1 mRNA expression after PCOS induction was not observed in the rats.

The roles of RFamide-related peptides (RFRPs), mammalian gonadotropin-inhibitory hormone (GnIH) orthologues in female reproduction.

OBJECTIVES: To benefit from reproduction and deal with challenges in the environmental conditions, animals must adapt internal physiology to maximize the reproduction rate. Maladaptive variations in the neurochemical systems and reproductive system can lead to manifestation of several significant mammalian reprocesses, including mammalian ovarian lifespan. RFamide-related peptide (RFRP, Rfrp), mammalian orthologues of gonadotropin-inhibitory hormone (GnIH), which is a regulator to prevent the gonadotropin-releasing hormone (GnRH) neural activity, is known to be related to reproductive traits. This review aimed to summarize recent five-year observations to outline historic insights and novel perspectives into the functions of RFRPs in coding the mammalian reproductive physiology, especially highlight recent advances in the impact on RFRPs in regulating mammalian ovary lifespan. MATERIALS AND METHODS: We reviewed the recent five-year important findings of RFRP system involved in mammalian ovary development. Data for this review were collected from Google Scholar and PubMed using the RFRP keyword combined with the keywords related to physiological or pathological reproductive functions. RESULTS: Recent discoveries are focused on three major fronts in research on RFRP role in female reproduction including reproductive functions, energy balance, and stress regulation. The roles of RFRPs in various development phases of mammal reproduction including prepuberty, puberty, estrous cycle, pregnancy, milking, menopause, and/or ovarian diseases have been shown. CONCLUSION: Overall, these recent advances demonstrate that RFRPs serve as critical mediators in mammalian ovarian development.

The Effects of Acoustic White Noise on the Rat Central Auditory System During the Fetal and Critical Neonatal Periods: A Stereological Study.

AIM: To evaluate the effects of long-term, moderate level noise exposure during crucial periods of rat infants on stereological parameters of medial geniculate body (MGB) and auditory cortex. MATERIALS AND METHODS: Twenty-four male offspring of 12 pregnant rats were divided into four groups: fetal-to-critical period group, which were exposed to noise from the last 10 days of fetal life till postnatal day (PND) 29; fetal period group that exposed to noise during the last 10 days of fetal life; critical period group, exposed to noise from PND 15 till PND 29, and control group. White noise at 90 dB for 2 h per day was used. STATISTICAL ANALYSIS USED: Variance for variables was performed using Proc GLM followed by mean comparison by Duncan's multiple range test. RESULTS: Numerical density of neurons in MGB of fetal-to-critical period group was lower than control group. Similar results were seen in numerical density of neurons in layers IV and VI of auditory cortex. Furthermore, no significant difference was observed in the volume of auditory cortex among groups, and only MGB volume in fetal-to-critical period group was higher than other groups. Estimated total number of neurons in MGB was not significantly different among groups. CONCLUSION: It seems necessary to prevent long-term moderate level noise exposure during fetal-to-critical neonatal period.

The Role of Arginine-Phenylalanine-Amide-Related Peptides in Mammalian Reproduction.

Until 2000 it was believed that gonadotropin-releasing hormone (GnRH) was the sole regulator of hypophyseal gonadotropes. In 2000, the discovery of a gonadotropin inhibitory hormone (GnIH) initiated a revolution in the field of reproductive physiology. Identification of GnIH homologues in mammals, the arginine-phenylalanine-amide (RFamide)-related peptides (RFRPs), indicated a similar function. Subsequently, further works conducted in various laboratories worldwide have shown that these neuropeptides inhibit the hypothalamic-hypophyseal axis. This review discusses the role of RFRPs in mammalian reproductive processes.

Increased Litter Size and Suckling Intensity Stimulate mRNA of RFamide-related Peptide in Rats.

BACKGROUND: RFamide-related peptide-3 (RFRP-3) inhibits gonadotropin releasing hormone (GnRH) and luteinizing hormone (LH) secretion in rats. This study evaluates the effects of litter size and suckling intensity on RFRP mRNA expression in the dorsomedial hypothalamic nucleus (DMH) of rats. MATERIALS AND METHODS: A total of 32 pregnant and 4 non-lactating ovariectomized (control group) Sprague-Dawley rats were used in this experimental study. Lactating rats were allotted to 8 equal groups. In 3 groups, the litter size was adjusted to 5, 10, or 15 pups upon parturition. Dams were allowed to suckle their pups continuously until 8 days postpartum. In the other 3 groups, the litter size was adjusted to 5 pups following birth. These pups were separated from the dams for 6 hours on day 8 postpartum, after which the pups were allowed to suckle for 2.5, 5, or 7.5 minutes prior to killing the dams. In 2 groups, lactating rats with 10 and 15 pups were separated from their pups for 6 hours on day 8 postpartum. In these groups, the pups were allowed to suckle their dams for 5 minutes before the dams were killed. All rats were killed on day 8 postpartum and the DMH was removed from each rat. We evaluated RFRP mRNA expression using realtime polymerase chain reaction (PCR). RESULTS: The expression of RFRP mRNA in the DMH increased with increased litter size and suckling intensity compared to the controls. The effect of suckling intensity on the expression of RFRP mRNA was more pronounced compared to the litter size. CONCLUSION: Increased litter size and suckling intensity stimulated RFRP mRNA expression in the DMH which might contribute to lactation anestrus in rats.

Expression of RFamide-Related Peptide-3 (RFRP-3) mRNA in Dorsomedial Hypothalamic Nucleus and KiSS-1 mRNA in Arcuate Nucleus of Rat during Pregnancy.

BACKGROUND: RFamide-related peptide-3 (RFRP-3) and kisspeptin (KiSS-1) are known to respectively inhibit and stimulate gonadotropin releasing hormone (GnRH) and lute- inizing hormone (LH) secretion in rat. The aim of the present study was to evaluate the relative mRNA expression of RFRP-3 and KiSS-1 in the hypothalamus of pregnant rats. MATERIALS AND METHODS: In a randomized controlled experimental study, the exact preg- nancy day of 18 Sprague-Dawley rats were confirmed using the vaginal smear method and were equally assigned to three groups of days 7, 14 and 21 of pregnancy. Four non- pregnant female rats were ovariectomized and assigned as the control group. All rats were decapitated, and the dorsomedial hypothalamic nucleus (DMH) and the arcuate nucleus (ARC) for detection of KiSS-1 mRNA were separated from their hypothalamus to detect RFRP-3 and KiSS-1 mRNA respectively. Then, their relative expressions were compared between control and pregnant groups using real-time polymerase chain reac- tion (PCR). RESULTS: The relative expression of RFRP-3 mRNA in DMH did not change significantly during pregnancy (p>0.01). However, the relative expression of KiSS-1 mRNA in ARC was at its highest in day 7 of pregnancy and decreased until day 21 of pregnancy (p<0.01). CONCLUSION: Decrease in GnRH and LH secretion during the pregnancy of rat may be controlled by constant expression of RFRP-3 mRNA and reduced expression of KiSS-1 mRNA in hypothalamus.