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Wang Y, Sun Q, Tang Q, Zhang Y, Tang M, Wang D, Wang Z. Progress of autonomic disturbances in narcolepsy type 1. Front Neurol 2023; 14:1107632. [PMID: 36949858 PMCID: PMC10025459 DOI: 10.3389/fneur.2023.1107632] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2022] [Accepted: 02/03/2023] [Indexed: 03/08/2023] Open
Abstract
Narcolepsy type 1 is a kind of sleep disorder characterized by a specific loss of hypocretin neurons in the lateral hypothalamus and reduced levels of hypocretin-1 in the cerebrospinal fluid. Hypocretin deficiency is associated with autonomic disorders. This article summarizes the autonomic disorders and possible mechanisms associated with narcolepsy type 1. Patients with narcolepsy type 1 often have various systemic autonomic symptoms, including non-dipping blood pressure, reduced heart rate variability, dynamic cerebral autoregulation impairment, reduced gastric motility and emptying, sleep-related erectile dysfunction, skin temperature abnormalities, and blunted pupillary light reflex. Similar findings should strengthen the recognition and intervention of these disturbances in clinical practice. In addition to hypocretin deficiency, current evidence also indicates that pharmacological therapy (including psychostimulants and anti-cataplectic drugs) and comorbidities may contribute to the alterations of autonomic system observed in narcolepsy type 1.
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Soejima Y, Iwata N, Nakayama N, Hirata S, Nakano Y, Yamamoto K, Suyama A, Oguni K, Nada T, Fujisawa S, Otsuka F. Mutual Effects of Orexin and Bone Morphogenetic Proteins on Gonadotropin Expression by Mouse Gonadotrope Cells. Int J Mol Sci 2022; 23:ijms23179782. [PMID: 36077179 PMCID: PMC9456022 DOI: 10.3390/ijms23179782] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2022] [Revised: 08/21/2022] [Accepted: 08/26/2022] [Indexed: 12/03/2022] Open
Abstract
Orexin plays a key role in the regulation of sleep and wakefulness and in feeding behavior in the central nervous system, but its receptors are expressed in various peripheral tissues including endocrine tissues. In the present study, we elucidated the effects of orexin on pituitary gonadotropin regulation by focusing on the functional involvement of bone morphogenetic proteins (BMPs) and clock genes using mouse gonadotrope LβT2 cells that express orexin type 1 (OX1R) and type 2 (OX2R) receptors. Treatments with orexin A enhanced LHβ and FSHβ mRNA expression in a dose-dependent manner in the absence of GnRH, whereas orexin A in turn suppressed GnRH-induced gonadotropin expression in LβT2 cells. Orexin A downregulated GnRH receptor expression, while GnRH enhanced OX1R and OX2R mRNA expression. Treatments with orexin A as well as GnRH increased the mRNA levels of Bmal1 and Clock, which are oscillational regulators for gonadotropin expression. Of note, treatments with BMP-6 and -15 enhanced OX1R and OX2R mRNA expression with upregulation of clock gene expression. On the other hand, orexin A enhanced BMP receptor signaling of Smad1/5/9 phosphorylation through upregulation of ALK-2/BMPRII among the BMP receptors expressed in LβT2 cells. Collectively, the results indicate that orexin regulates gonadotropin expression via clock gene expression by mutually interacting with GnRH action and the pituitary BMP system in gonadotrope cells.
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Affiliation(s)
- Yoshiaki Soejima
- Department of General Medicine, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, 2-5-1 Shikata-cho, Kitaku, Okayama 700-8558, Japan
| | - Nahoko Iwata
- Department of General Medicine, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, 2-5-1 Shikata-cho, Kitaku, Okayama 700-8558, Japan
| | - Nanako Nakayama
- Department of General Medicine, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, 2-5-1 Shikata-cho, Kitaku, Okayama 700-8558, Japan
| | - Shinichi Hirata
- Department of General Medicine, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, 2-5-1 Shikata-cho, Kitaku, Okayama 700-8558, Japan
| | - Yasuhiro Nakano
- Department of General Medicine, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, 2-5-1 Shikata-cho, Kitaku, Okayama 700-8558, Japan
| | - Koichiro Yamamoto
- Department of General Medicine, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, 2-5-1 Shikata-cho, Kitaku, Okayama 700-8558, Japan
| | - Atsuhito Suyama
- Department of General Medicine, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, 2-5-1 Shikata-cho, Kitaku, Okayama 700-8558, Japan
| | - Kohei Oguni
- Department of General Medicine, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, 2-5-1 Shikata-cho, Kitaku, Okayama 700-8558, Japan
| | - Takahiro Nada
- Department of General Medicine, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, 2-5-1 Shikata-cho, Kitaku, Okayama 700-8558, Japan
| | - Satoshi Fujisawa
- Department of Nephrology, Rheumatology, Endocrinology and Metabolism, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, 2-5-1 Shikata-cho, Kitaku, Okayama 700-8558, Japan
| | - Fumio Otsuka
- Department of General Medicine, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, 2-5-1 Shikata-cho, Kitaku, Okayama 700-8558, Japan
- Correspondence: ; Tel.: +81-86-235-7342; Fax: +81-86-235-7345
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Grasselli F, Bussolati S, Grolli S, Di Lecce R, Dall’Aglio C, Basini G. Effects of Orexin B on Swine Granulosa and Endothelial Cells. Animals (Basel) 2021; 11:ani11061812. [PMID: 34204547 PMCID: PMC8235033 DOI: 10.3390/ani11061812] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2021] [Revised: 06/03/2021] [Accepted: 06/15/2021] [Indexed: 12/25/2022] Open
Abstract
Simple Summary The follicle is the ovarian functional unit. It is mainly composed of granulosa cells and angiogenesis is crucial to guarantee its development till ovulation. Carrying on our previous studies on the orexin system in the ovary, we presently demonstrate a potential role of orexin B in the control of granulosa cells’ oxidative stress and of the angiogenesis event. Abstract In addition to the well-known central modulatory role of orexins, we recently demonstrated a peripheral involvement in swine granulosa cells for orexin A and in adipose tissue for orexin B (OXB). The aim of present research was to verify immunolocalization of OXB and its potential role in modulating the main features of swine granulosa cells. In particular, we explored the effects on granulosa cell proliferation (through the incorporation of bromodeoxyuridine), cell metabolic activity (as indirect evaluation by the assessment of ATP), steroidogenic activity (by immunoenzymatic examination) and redox status (evaluating the production of superoxide anion by means of the WST test, production of nitric oxide through the use of the Griess test and the non-enzymatic reducing power by FRAP test). Our data point out that OXB does not modify granulosa cell growth, steroidogenesis and superoxide anion generation. On the contrary, the peptide stimulates (p < 0.05) nitric oxide output and non-enzymatic reducing power. Since new vessel growth is crucial for ovarian follicle development, a further aim of this study was to explore the expression of prepro-orexin and the effects of OXB on swine aortic endothelial cells. We found that the peptide is ineffective in modulating cell growth, while it inhibits redox status parameters. In addition, we demonstrated a stimulatory effect on angiogenesis evaluated in fibrin gel angiogenesis assay. Taken together, OXB appears to be potentially involved in the modulation of redox status in granulosa and endothelial cells and we could argue an involvement of the peptide in the follicular angiogenic events.
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Affiliation(s)
- Francesca Grasselli
- Dipartimento di Scienze Medico-Veterinarie, Università degli Studi di Parma, Via del Taglio 10, 43126 Parma, Italy; (F.G.); (S.B.); (S.G.); (R.D.L.)
| | - Simona Bussolati
- Dipartimento di Scienze Medico-Veterinarie, Università degli Studi di Parma, Via del Taglio 10, 43126 Parma, Italy; (F.G.); (S.B.); (S.G.); (R.D.L.)
| | - Stefano Grolli
- Dipartimento di Scienze Medico-Veterinarie, Università degli Studi di Parma, Via del Taglio 10, 43126 Parma, Italy; (F.G.); (S.B.); (S.G.); (R.D.L.)
| | - Rosanna Di Lecce
- Dipartimento di Scienze Medico-Veterinarie, Università degli Studi di Parma, Via del Taglio 10, 43126 Parma, Italy; (F.G.); (S.B.); (S.G.); (R.D.L.)
| | - Cecilia Dall’Aglio
- Dipartimento di Medicina Veterinaria, Università degli Studi di Perugia, Via San Costanzo 4, 06126 Perugia, Italy;
| | - Giuseppina Basini
- Dipartimento di Scienze Medico-Veterinarie, Università degli Studi di Parma, Via del Taglio 10, 43126 Parma, Italy; (F.G.); (S.B.); (S.G.); (R.D.L.)
- Correspondence: ; Tel.: +39-521-032-775
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Mohammadi S, Moosaie F, Saghazadeh A, Mahmoudi M, Rezaei N. Metabolic profile in patients with narcolepsy: a systematic review and meta-analysis. Sleep Med 2021; 81:268-284. [PMID: 33740593 DOI: 10.1016/j.sleep.2021.02.040] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Revised: 02/10/2021] [Accepted: 02/16/2021] [Indexed: 11/25/2022]
Abstract
Narcolepsy, a sleep disorder characterized by loss of hypocretin neurons, has been associated with metabolic disturbances. Although the metabolic alterations in narcolepsy patients are widely investigated in the literature, the results are controversial. We performed a systematic search of literature to identify metabolic profiling studies in narcolepsy patients. A total of 48 studies were included in the meta-analysis. Narcolepsy patients exhibited higher prevalence of obesity (log OR = 0.93 [0.73-1.13], P < 0.001), diabetes mellitus (log OR = 0.64 [0.34, 0.94], P < 0.001), hypertension (log OR = 0.33 [0.11, 0.55], P < 0.001), and dyslipidemia (log OR = 1.19 [0.60, 1.77], P < 0.001) compared with non-narcoleptic controls. Narcolepsy was associated with higher BMI (SMD = 0.50 [0.32-0.68], P < 0.001), waist circumference (MD = 8.61 [2.03-15.19], P = 0.01), and plasma insulin (SMD = 0.61 [0.14-1.09], P = 0.01). Levels of fasting blood glucose (SMD = -0.25 [-0.61,0.10], P = 0.15), BMR-RMR (SMD = -0.17 [-0.52-0.18], P = 0.34), systolic blood pressure (SMD = 0.29 [-0.39-0.97], P = 0.40), diastolic blood pressure (SMD = 0.39 [-0.62, 1.40], P = 0.45), CSF melanin-concentrating hormone (MD = 5.56 [-30.79-41.91], P = 0.76), serum growth hormone (SMD = 7.84 [-7.90-23.57], P = 0.33), as well as plasma and CSF leptin (SMD = 0.10 [-1.32-1.51], P = 0.89 and MD = 0.01 [-0.02-0.04], P = 0.56, respectively) did not significantly differ between narcolepsy patients and controls. These findings necessitate early screening of metabolic alterations and cardiovascular risk factors in narcolepsy patients to reduce the morbidity and mortality rates.
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Affiliation(s)
- Soheil Mohammadi
- School of Medicine, Tehran University of Medical Sciences, Tehran, Iran; NeuroImaging Network (NIN), Universal Scientific Education and Research Network (USERN), Tehran University of Medical Sciences, Tehran, Iran
| | - Fatemeh Moosaie
- School of Medicine, Tehran University of Medical Sciences, Tehran, Iran; NeuroImaging Network (NIN), Universal Scientific Education and Research Network (USERN), Tehran University of Medical Sciences, Tehran, Iran
| | - Amene Saghazadeh
- Research Center for Immunodeficiencies, Children's Medical Center, Tehran University of Medical Sciences, Tehran, Iran; MetaCognition Interest Group (MCIG), Universal Scientific Education and Research Network (USERN), Tehran, Iran
| | - Maryam Mahmoudi
- Department of Cellular Molecular Nutrition, School of Nutritional Sciences and Dietetics, Tehran University of Medical Sciences, Tehran, Iran; Dietitians and Nutrition Experts Team (DiNET), Universal Scientific Education and Research Network (USERN), Tehran, Iran
| | - Nima Rezaei
- Research Center for Immunodeficiencies, Children's Medical Center, Tehran University of Medical Sciences, Tehran, Iran; Department of Immunology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran; Systematic Review and Meta-analysis Expert Group (SRMEG), Universal Scientific Education and Research Network (USERN), Tehran, Iran.
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Biobaku F, Hanna A, Matthews G, Dhindsa S, Dandona P. Narcolepsy, depression, and severe flushing in an obese man. Clin Case Rep 2020; 8:1824-1826. [PMID: 32983505 PMCID: PMC7495789 DOI: 10.1002/ccr3.2873] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2019] [Revised: 12/18/2019] [Accepted: 01/07/2020] [Indexed: 11/07/2022] Open
Abstract
Hypogonadism as a cause of depression, daytime sleepiness, and flushing is often missed in young males. Our case report highlights the importance of screening for hypogonadotropic hypogonadism and its treatment in symptomatic men with severe obesity, especially if they have depression, excessive sleepiness, and narcolepsy.
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Affiliation(s)
- Fatimo Biobaku
- Division of Endocrinology, Diabetes and MetabolismState University of New York at BuffaloBuffaloNew York
| | - Adel Hanna
- Division of Endocrinology, Diabetes and MetabolismState University of New York at BuffaloBuffaloNew York
| | - George Matthews
- Division of CardiologyState University of New York at BuffaloBuffaloNew York
| | - Sandeep Dhindsa
- Division of Endocrinology, Diabetes and MetabolismSaint Louis UniversitySaint LouisMissouri
| | - Paresh Dandona
- Division of Endocrinology, Diabetes and MetabolismState University of New York at BuffaloBuffaloNew York
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Dunietz GL, Vanini G, Shannon C, O'Brien LM, Chervin RD. Associations of plasma hypocretin-1 with metabolic and reproductive health: Two systematic reviews of clinical studies. Sleep Med Rev 2020; 52:101307. [PMID: 32259696 PMCID: PMC7351596 DOI: 10.1016/j.smrv.2020.101307] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2019] [Revised: 01/30/2020] [Accepted: 01/31/2020] [Indexed: 12/11/2022]
Abstract
The hypocretin system consists of two peptides hypocretin-1 and hypocretin-2 (HCRT1 and HCRT2). Hypocretin-containing neurons are located in the posterior and lateral hypothalamus, and have widespread projections throughout the brain and spinal cord. In addition to its presence in the cerebrospinal fluid (CSF), peripheral HCRT1 has been detected in plasma. Robust experimental evidence demonstrates functions of hypothalamic-originated HCRT1 in regulation of multiple biological systems related to sleep-wake states, energy homeostasis and endocrine function. In contrast, HCRT1 studies with human participants are limited by the necessarily invasive assessment of CSF HCRT1 to patients with underlying morbidity. Regulation by HCRT1 of energy homeostasis and reproduction in animals suggests similar regulation in humans and prompts these two systematic reviews. These reviews translate prior experimental findings from animal studies to humans and examine associations between HCRT1 and: 1) metabolic risk factors; 2) reproductive function in men, women and children. A total of 21 studies and six studies met the inclusion criteria for the two searches, respectively. Research question, study design, study population, assessments of HCRT1, reproductive, cardiometabolic data and main findings were extracted. Associations between HCRT1, metabolic and reproductive function are inconsistent. Limitations of studies and future research directions are outlined.
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Affiliation(s)
- Galit L Dunietz
- Division of Sleep Medicine, Department of Neurology, University of Michigan, Ann Arbor, MI, 48109, USA.
| | - Giancarlo Vanini
- Department of Anesthesiology, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Carol Shannon
- Taubman Health Sciences Library, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Louise M O'Brien
- Division of Sleep Medicine, Department of Neurology, University of Michigan, Ann Arbor, MI, 48109, USA; Department of Obstetrics & Gynecology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Ronald D Chervin
- Division of Sleep Medicine, Department of Neurology, University of Michigan, Ann Arbor, MI, 48109, USA
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Firouzabadi N, Navabzadeh N, Moghimi-Sarani E, Haghnegahdar M. Orexin/Hypocretin Type 2 Receptor (HCRTR2) Gene as a Candidate Gene in Sertraline-Associated Insomnia in Depressed Patients. Neuropsychiatr Dis Treat 2020; 16:1121-1128. [PMID: 32440126 PMCID: PMC7210038 DOI: 10.2147/ndt.s250141] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/19/2020] [Accepted: 04/22/2020] [Indexed: 11/23/2022] Open
Abstract
BACKGROUND Selective serotonin reuptake inhibitors (SSRIs) are considered as first-line drugs for treating depressive disorders. Among the adverse effects reported with sertraline is sleep disturbances; however, the etiology lying beneath is obscure. Orexin, the most recently discovered neurotransmitter, is involved in the sleep cycle. It exerts its physiological actions through orexin or hypocretin type 1 and 2 receptors (HCRTR1 and HCRTR2). Dysfunction of the orexin system contributes to various psychiatric, neurologic and neuropsychiatric disorders. Thus, our study aimed to assess the possible association of genetic variation of HCRTR2 G1246A with hypersomnia reported with sertraline in a group of major depressive disorder (MDD) patients. PATIENTS AND METHODS Ninety-six newly diagnosed MDD patients were enrolled in our cohort study. MDD was assessed using DSM-V criteria. Insomnia Severity Index (ISI) was used to assess insomnia at baseline (week 0) and week 4. Blood samples were collected for further genotyping of HCRTR2 G1246A (rs2653349) using polymerase chain reaction-restriction fragment length polymorphism. RESULTS A significant association between G1264A polymorphism of HCRTR2 and insomnia was observed. Insomnia with sertraline happens by 2.5-fold (P=0.022; odds ratio (OR)=2.5; 95% confidence interval (CI): 1.1-5.7) in patients having GG genotype. Patients with G allele experience insomnia by 2.1-fold more than A allele carriers (P=0.022; OR=2.1; 95% CI= 1.1-4.0). Subgroup analysis showed a significant association between GG genotype as well as the G allele and insomnia only in female MDD patients (P=0.011; OR=4.0; 95% CI=1.3-12.0 and P=0.033; OR=2.4; 95% CI=1.02-5.7, respectively). CONCLUSION In conclusion, the G1246A variant might be a predictor for insomnia in MDD patients treated with sertraline. Our findings support the idea that some variants of the HCRTR might contribute to inter-individual variability in the sleep pattern of patients receiving antidepressants.
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Affiliation(s)
- Negar Firouzabadi
- Department of Pharmacology and Toxicology, School of Pharmacy, Shiraz University of Medical Sciences, Shiraz, Iran.,Pharmaceutical Sciences Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Niloofar Navabzadeh
- Department of Pharmacology and Toxicology, School of Pharmacy, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Ebrahim Moghimi-Sarani
- Department of Psychiatry, School of Medicine, Shiraz University of Medical Sciences, School of Medicine, Shiraz, Iran
| | - Maral Haghnegahdar
- Department of Pharmacology and Toxicology, School of Pharmacy, Shiraz University of Medical Sciences, Shiraz, Iran
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Lee DS, Choi JB, Sohn DW. Impact of Sleep Deprivation on the Hypothalamic–Pituitary–Gonadal Axis and Erectile Tissue. J Sex Med 2019; 16:5-16. [DOI: 10.1016/j.jsxm.2018.10.014] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2018] [Revised: 10/19/2018] [Accepted: 10/29/2018] [Indexed: 01/24/2023]
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Liguori G, Squillacioti C, Assisi L, Pelagalli A, Vittoria A, Costagliola A, Mirabella N. Potential role of orexin A binding the receptor 1 for orexins in normal and cryptorchid dogs. BMC Vet Res 2018; 14:55. [PMID: 29482574 PMCID: PMC5828418 DOI: 10.1186/s12917-018-1375-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2016] [Accepted: 02/15/2018] [Indexed: 01/17/2023] Open
Abstract
Background Cryptorchidism is one of the most common birth disorders of the male reproductive system identified in dogs and other mammals. This condition is characterised by the absence of one (unilateral) or both (bilateral) gonads from the scrotum. The peptides orexin A (OxA) and B (OxB) were obtained by post-transcriptional proteolytic cleavage of a precursor molecule, called prepro-orexin. These substances bind two types of G-coupled receptors called receptor 1 (OX1R) and 2 (OX2R) for orexins. OX1R is specific to OxA while OX2R binds the two peptides with equal affinity. Orexins modulate a great variety of body functions, such as the reproductive mechanism. The purpose of the present research was to study the presence of OxA and its receptor 1 and their possible involvement in the canine testis under healthy and pathological conditions. Methods This study was performed using adult male normal dogs and male dogs affected by unilateral cryptorchidism. Tissue samples were collected from testes and were divided into three groups: normal, contralateral and cryptic. The samples were used for immunohistochemistry, Western blot and in vitro tests for testosterone evaluation in normal and pathological conditions. Results OxA-immunoreactivity (IR) was described in interstitial Leydig cells of the normal gonad, and Leydig, Sertoli cells and gonocytes in the cryptic gonad. In the normal testis, OX1R-IR was described in Leydig cells, in pachytene and second spermatocytes and in immature and mature spermatids throughout the stages of the germ developing cycle of the male gonad. In the cryptic testis OX1R-IR was distributed in Leydig and Sertoli cells. The presence of prepro-orexin and OX1R was demonstrated by Western blot analysis. The incubation of fresh testis slices with OxA caused the stimulation of testosterone synthesis in the normal and cryptic gonad while the steroidogenic OxA-induced effect was cancelled by adding the selective OX1R antagonist SB-408124. Conclusions These results led us to hypothesise that OxA binding OX1R might be involved in the modulation of spermatogenesis and steroidogenesis in canine testis in healthy and pathological conditions.
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Affiliation(s)
- Giovanna Liguori
- Department of Veterinary Medicine and Animal Production, University of Naples "Federico II", Via Delpino 1, 80137, Naples, Italy.
| | - Caterina Squillacioti
- Department of Veterinary Medicine and Animal Production, University of Naples "Federico II", Via Delpino 1, 80137, Naples, Italy
| | - Loredana Assisi
- Department of Biology, University of Naples "Federico II", Via Mezzocannone 6, 80134, Naples, Italy
| | - Alessandra Pelagalli
- Department of Advanced Biomedical Sciences, University of Naples "Federico II", Via Pansini 5, 80131, Naples, Italy.,Institute of Biostructures and Bioimages, National Research Council, Via De Amicis 95, 80131, Naples, Italy
| | - Alfredo Vittoria
- Department of Veterinary Medicine and Animal Production, University of Naples "Federico II", Via Delpino 1, 80137, Naples, Italy
| | - Anna Costagliola
- Department of Veterinary Medicine and Animal Production, University of Naples "Federico II", Via Delpino 1, 80137, Naples, Italy
| | - Nicola Mirabella
- Department of Veterinary Medicine and Animal Production, University of Naples "Federico II", Via Delpino 1, 80137, Naples, Italy
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Kaminski T, Smolinska N, Kiezun M, Dobrzyn K, Szeszko K, Maleszka A. Effect of orexin B on CYP17A1 and CYP19A3 expression and oestradiol, oestrone and testosterone secretion in the porcine uterus during early pregnancy and the oestrous cycle. Animal 2018; 12:1921-32. [PMID: 29366436 DOI: 10.1017/S1751731117003779] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Orexin A (OXA) and B (OXB) are hypothalamic neuropeptides identified as regulators of food intake, energy homoeostasis, sleep-wake cycle and arousal. They also create an integrative link between energy homoeostasis and reproduction. Although their functions in the ovaries and testes have been partially explored, to date, less attention has been focused on the role of the peptides in the uterus. The aim of this study was to investigate the effect of one of orexins - orexin B on oestradiol (E2), oestrone (E1) and testosterone (T) secretion by porcine endometrial and myometrial slices as well as the gene expression of key steroidogenic enzymes responsible for steroid production (CYP17A1, CYP19A3) during the luteal phase of the oestrous cycle (days 10 to 11) and early pregnancy (days 10 to 11, 12 to 13, 15 to 16, 27 to 28). Orexin B suppressed E2 secretion by endometrial slices on days 10 to 11 and 15 to 16 of pregnancy, and days 10 to 11 of the cycle. In the myometrium, OXB inhibited E2 production on days 10 to 11 of pregnancy, whereas on days 12 to 13 it enhanced steroid output. Endometrial E1 release was potentiated by the peptide during all studied periods of the cycle and pregnancy, with the exception of days 12 to 13, when an inhibitory effect was observed. Myometrial secretion of E1 was increased, except on days 27 to 28. Testosterone secretion by endometrial slices was increased on days 12 to 13 and 27 to 28 of pregnancy. On days 10 to 11 of the cycle, T release was stimulated in response to the lowest and decreased under the influence of the highest dose of OXB. In the myometrium, T production was inhibited by OXB on days 10 to 11 of pregnancy and during the corresponding period of the cycle. On days 27 to 28 of pregnancy, T release was potentiated by the lowest dose of OXB. Expression of both genes was modified by OXB depending on the period of pregnancy and the type of examined uterine tissues. Our findings suggest that OXB, through modulation of uterine steroidogenesis, may have a regulatory role in the uterus.
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Cataldi NI, Lux-Lantos VA, Libertun C. Perinatal programming of the orexinergic (hypocretinergic) system in hypothalamus and anterior pituitary by testosterone. Peptides 2018; 99:117-127. [PMID: 28442349 DOI: 10.1016/j.peptides.2017.04.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/11/2016] [Revised: 04/18/2017] [Accepted: 04/19/2017] [Indexed: 01/12/2023]
Abstract
Orexins A/B derived from hypothalamic prepro-orexin (PPO) are agonists for orexin receptors 1 (OX1) and 2 (OX2). Previously, we showed clear sex differences in the hypothalamic-pituitary-gonadal orexinergic system in adult rodents. Here, we studied the effect of sexual brain differentiation on the orexinergic system in neuroendocrine structures regulating reproduction. We evaluated: a: proestrous and neonatally androgenized female rats; b: adult males, untreated or gonadectomized in adulthood and injected with oil or estradiol and progesterone (E2/P4); c: control and demasculinized males (perinatally treated with flutamide and later castration) injected either with oil or E2/P4 in adulthood. Rats were sacrificed at 12:00 and 18:00h; blood samples and brains were collected. Hormones were measured using radioimmunoassay. PPO, OX1 and OX2 mRNAs were quantified by qPCR in medial basal hypothalamus, anterior hypothalamus, adenohypophysis, and cortex. Western blots for OX1 were done in the same structures. In normal females, gonadotropins surged at 18:00h coinciding with significant elevations of PPO, OX1 and OX2 mRNAs and OX1 protein in hypothalamus and pituitary; no increases were observed at noon. Afternoon changes were absent in masculinized females. Demasculinized males when treated with E2/P4 showed high PPO, OX1 and OX2 mRNAs and OX1 protein expression in hypothalamus and pituitary at 12:00 and 18:00h compared vehicle-treated controls. The same steroid treatment was ineffective in males with normal brain masculinization. Here we show that neonatal testosterone shapes the sexual differences in the hypothalamic-pituitary orexinergic system in synchronicity to establishing the brain sex differences of the reproductive axis. The female brain controls gonadotropin surges and concurrent elevations of all studied components of the orexinergic system, suggesting its participation as a possible link between food intake, behavior and hormonal control of reproduction.
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Affiliation(s)
| | | | - Carlos Libertun
- Instituto de Biología y Medicina Experimental-CONICET, Argentina; Universidad de Buenos Aires, Facultad de Medicina, Departamento de Fisiología y Biofísica, Buenos Aires, Argentina.
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Skrapits K, Kanti V, Savanyú Z, Maurnyi C, Szenci O, Horváth A, Borsay BÁ, Herczeg L, Liposits Z, Hrabovszky E. Lateral hypothalamic orexin and melanin-concentrating hormone neurons provide direct input to gonadotropin-releasing hormone neurons in the human. Front Cell Neurosci 2015; 9:348. [PMID: 26388735 PMCID: PMC4559643 DOI: 10.3389/fncel.2015.00348] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2015] [Accepted: 08/20/2015] [Indexed: 12/03/2022] Open
Abstract
Hypophysiotropic projections of gonadotropin-releasing hormone (GnRH)-synthesizing neurons form the final common output way of the hypothalamus in the neuroendocrine control of reproduction. Several peptidergic neuronal systems of the medial hypothalamus innervate human GnRH cells and mediate crucially important hormonal and metabolic signals to the reproductive axis, whereas much less is known about the contribution of the lateral hypothalamic area to the afferent control of human GnRH neurons. Orexin (ORX)- and melanin-concentrating hormone (MCH)-synthesizing neurons of this region have been implicated in diverse behavioral and autonomic processes, including sleep and wakefulness, feeding and other functions. In the present immunohistochemical study, we addressed the anatomical connectivity of these neurons to human GnRH cells in post-mortem hypothalamic samples obtained from autopsies. We found that 38.9 ± 10.3% and 17.7 ± 3.3% of GnRH-immunoreactive (IR) perikarya in the infundibular nucleus of human male subjects received ORX-IR and MCH-IR contacts, respectively. On average, each 1 mm segment of GnRH dendrites received 7.3 ± 1.1 ORX-IR and 3.7 ± 0.5 MCH-IR axo-dendritic appositions. Overall, the axo-dendritic contacts dominated over the axo-somatic contacts and represented 80.5 ± 6.4% of ORX-IR and 76.7 ± 4.6% of MCH-IR inputs to GnRH cells. Based on functional evidence from studies of laboratory animals, the direct axo-somatic and axo-dendritic input from ORX and MCH neurons to the human GnRH neuronal system may convey critical metabolic and other homeostatic signals to the reproducive axis. In this study, we also report the generation and characterization of new antibodies for immunohistochemical detection of GnRH neurons in histological sections.
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Affiliation(s)
- Katalin Skrapits
- Laboratory of Endocrine Neurobiology, Institute of Experimental Medicine, Hungarian Academy of Sciences Budapest, Hungary
| | - Vivien Kanti
- Laboratory of Endocrine Neurobiology, Institute of Experimental Medicine, Hungarian Academy of Sciences Budapest, Hungary
| | - Zsófia Savanyú
- Laboratory of Endocrine Neurobiology, Institute of Experimental Medicine, Hungarian Academy of Sciences Budapest, Hungary
| | - Csilla Maurnyi
- Laboratory of Endocrine Neurobiology, Institute of Experimental Medicine, Hungarian Academy of Sciences Budapest, Hungary
| | - Ottó Szenci
- Department and Clinic for Production Animals, Faculty of Veterinary Science, Szent István University Üllő, Hungary ; MTA-SZIE Large Animal Clinical Research Group, Dóra major Üllő, Hungary
| | - András Horváth
- Department and Clinic for Production Animals, Faculty of Veterinary Science, Szent István University Üllő, Hungary
| | - Beáta Á Borsay
- Department of Forensic Medicine, Faculty of Medicine of the University of Debrecen Debrecen, Hungary
| | - László Herczeg
- Department of Forensic Medicine, Faculty of Medicine of the University of Debrecen Debrecen, Hungary
| | - Zsolt Liposits
- Laboratory of Endocrine Neurobiology, Institute of Experimental Medicine, Hungarian Academy of Sciences Budapest, Hungary ; Department of Neuroscience, Faculty of Information Technology and Bionics, Pázmány Péter Catholic University Budapest, Hungary
| | - Erik Hrabovszky
- Laboratory of Endocrine Neurobiology, Institute of Experimental Medicine, Hungarian Academy of Sciences Budapest, Hungary
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Li J, Hu Z, de Lecea L. The hypocretins/orexins: integrators of multiple physiological functions. Br J Pharmacol 2014; 171:332-50. [PMID: 24102345 DOI: 10.1111/bph.12415] [Citation(s) in RCA: 181] [Impact Index Per Article: 18.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2013] [Revised: 07/16/2013] [Accepted: 08/02/2013] [Indexed: 12/28/2022] Open
Abstract
The hypocretins (Hcrts), also known as orexins, are two peptides derived from a single precursor produced in the posterior lateral hypothalamus. Over the past decade, the orexin system has been associated with numerous physiological functions, including sleep/arousal, energy homeostasis, endocrine, visceral functions and pathological states, such as narcolepsy and drug abuse. Here, we review the discovery of Hcrt/orexins and their receptors and propose a hypothesis as to how the orexin system orchestrates these multifaceted physiological functions.
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Affiliation(s)
- Jingcheng Li
- Department of Physiology, Third Military Medical University, Chongqing, China
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Nitkiewicz A, Smolinska N, Maleszka A, Chojnowska K, Kaminski T. Expression of orexins and their precursor in the porcine ovary and the influence of orexins on ovarian steroidogenesis in pigs. Anim Reprod Sci 2014; 148:53-62. [PMID: 24916957 DOI: 10.1016/j.anireprosci.2014.03.015] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2013] [Revised: 03/16/2014] [Accepted: 03/23/2014] [Indexed: 11/30/2022]
Abstract
Orexins A and B are hypothalamic neuropeptides associated with homeostasis and the reproductive system. The aim of the study was to compare the expression of the prepro-orexin gene and the intensity of orexins immunoreactivity in the porcine ovary (corpora lutea, granulosa and theca interna cells) during four different stages of the oestrous cycle (days: 2-3, 10-12, 14-16 and 17-19) and to examine the in vitro effect of orexins on the secretion of steroid hormones by porcine luteal, granulosa and theca interna cells. The highest expression of prepro-orexin mRNA was observed in theca interna cells on days 17-19 of the oestrous cycle. The highest content of immunoreactive orexin A was noted in corpora lutea on days 10-12 and the highest level of immunoreactive orexin B on days 14-16 of the cycle. Immunoreactive orexin A concentrations were higher in theca interna cells than in granulosa cells, whereas similar levels of immunoreactive orexin B were observed in both cell types. Under in vitro conditions, at the concentration of 10 nM, orexins A and B inhibited FSH-induced oestradiol secretion by granulosa cells. The obtained results suggest that the pattern of orexin peptide expression in the porcine ovary is related to the animals' hormonal status. Our findings imply that orexins can affect porcine reproductive functions through modulation of ovarian steroidogenesis.
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Affiliation(s)
- Anna Nitkiewicz
- Department of Animal Physiology, University of Warmia and Mazury in Olsztyn, ul. Oczapowskiego 1A, 10-719 Olsztyn, Poland
| | - Nina Smolinska
- Department of Animal Physiology, University of Warmia and Mazury in Olsztyn, ul. Oczapowskiego 1A, 10-719 Olsztyn, Poland
| | - Anna Maleszka
- Department of Animal Physiology, University of Warmia and Mazury in Olsztyn, ul. Oczapowskiego 1A, 10-719 Olsztyn, Poland
| | - Katarzyna Chojnowska
- Department of Animal Physiology, University of Warmia and Mazury in Olsztyn, ul. Oczapowskiego 1A, 10-719 Olsztyn, Poland
| | - Tadeusz Kaminski
- Department of Animal Physiology, University of Warmia and Mazury in Olsztyn, ul. Oczapowskiego 1A, 10-719 Olsztyn, Poland.
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Cataldi NI, Lux Lantos VA, Libertun C. Orexin A and B in vitro modify orexins receptors expression and gonadotropins secretion of anterior pituitary cells of proestrous rats. ACTA ACUST UNITED AC 2014; 188:25-30. [PMID: 24333629 DOI: 10.1016/j.regpep.2013.12.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2013] [Revised: 11/27/2013] [Accepted: 12/04/2013] [Indexed: 11/22/2022]
Abstract
AIM Orexin A and orexin B (hypocretins) are neuropeptides synthesized mainly by neurons located in the lateral hypothalamus and projections throughout the brain. They are agonists at both the orexin 1 and orexin 2G protein-coupled receptors. They have been related to arousal, sleep and feeding, autonomic and neuroendocrine functions. Their role in the brain control of gonadotropins secretion was postulated in rodents and humans. Previously, we demonstrated the participation of the orexinergic system in attaining successful reproduction in in vivo studies. METHODS We studied in vitro the effects of both neuropeptides, in the presence or absence of selective antagonists, on the mRNA expression of orexin 1 and orexin 2 receptors in anterior pituitary cells of proestrous rats, as well as the direct effects on FSH and LH secretion. RESULTS Both orexin A and orexin B increased FSH and LH secretion; these effects were suppressed by the orexin 1 receptor blocking agent SB-334867 and the orexin 2 receptor antagonists JNJ-10397049. Orexin A and orexin B decreased OX1 receptor mRNA expression and this effect was modified only when both blocking agents were present. Neither orexin A nor the blocking drugs by themselves modified OX2 receptor mRNA expression. Orexin B treatment increased the mRNA expression of OX2 receptor. The effect was abolished only by the OX2 receptor antagonist. CONCLUSION In an in vitro model, we demonstrated a direct effect of orexins on gonadotropins release and orexins receptors expression, underlining the hypothesis that orexins participate in the brain control of pituitary functions.
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Huda MSB, Mani H, Durham BH, Dovey TM, Halford JCG, Aditya BS, Pinkney JH, Wilding JP, Hart IK. Plasma obestatin and autonomic function are altered in orexin-deficient narcolepsy, but ghrelin is unchanged. Endocrine 2013. [PMID: 23179778 DOI: 10.1007/s12020-012-9838-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Narcolepsy-cataplexy is characterised by orexin deficiency, sleep disturbance, obesity and dysautonomia. Ghrelin and obestatin affect both energy intake and sleep. Our aim was to investigate ghrelin, obestatin and metabolic/autonomic function in narcolepsy-cataplexy. Eight narcolepsy-cataplexy patients (seven CSF orexin-deficient) and eight matched controls were studied. The subjects had a fixed energy meal with serial blood samples and measurement of heart rate variability (HRV). Fasting plasma obestatin was more than threefold higher in narcolepsy subjects (narcolepsy 89.6 ± 16 pg/ml vs. control 24.9 ± 3 pg/ml, p < 0.001). There was no change in HRV total power, but post-prandial low-frequency (LF) power and high-frequency (HF) power were lower in the narcolepsy group [area under the curve (AUC): HF power narcolepsy 1.4 × 10(5) ± 0.2 × 10(5) vs. control 3.3 × 10(5) ± 0.6 × 10(5 )ms(2)/h, p < 0.001]. On multiple regression analyses, the only significant predictor of plasma obestatin was HF power, which was inversely correlated with obestatin (β = -0.65 R (2) = 38 %, p = 0.009). Fasting and post-prandial plasma ghrelin were similar in both groups (narcolepsy 589.5 ± 88 pg/ml vs. control 686.9 ± 81 pg/ml, p = 0.5; post-prandial AUC-narcolepsy 161.3 ± 22 ng/ml/min vs. control 188.6 ± 62 ng/ml/min, p = 0.4). Only the narcolepsy group had significant suppression of plasma ghrelin after the meal (ANOVA, p = 0.004). In orexin-deficient narcolepsy, fasting plasma ghrelin is unaltered, and post-prandial suppression is preserved. Fasting plasma obestatin is increased and correlates with autonomic dysfunction. As obestatin affects NREM sleep, we suggest that increased plasma levels contribute to the disrupted sleep-state control in narcolepsy.
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Affiliation(s)
- M S B Huda
- University of Liverpool Diabetes and Endocrinology Research Group, Clinical Sciences Centre, University Hospital Aintree, Liverpool, L9 7AL, UK.
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Abstract
Obstructive sleep apnea (OSA) is a complicated disease with an unrecognized mechanism. Obesity, sex, age, and smoking have been found to be independent correlates of OSA. Orexin (also named hypocretin) mainly secreted by lateral hypothalamus neurons has a wide array of biological functions like regulating sleep, energy levels and breathing. Several clinical studies found ties between orexin and OSA. Because of the close correlation between orexin and obesity, sex, age and smoking (which are the key risk factors for OSA patients), we hypothesize that orexin may play a key role in the pathogenesis of OSA.
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Affiliation(s)
- Wei Wang
- Institute of Stomatology, Nanjing Medical University, Department of Orthodontics, Affiliated Hospital of Stomatology, Nanjing Medical University, Nanjing 210029, China
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Poli F, Pizza F, Mignot E, Ferri R, Pagotto U, Taheri S, Finotti E, Bernardi F, Pirazzoli P, Cicognani A, Balsamo A, Nobili L, Bruni O, Plazzi G. High prevalence of precocious puberty and obesity in childhood narcolepsy with cataplexy. Sleep 2013; 36:175-81. [PMID: 23372264 DOI: 10.5665/sleep.2366] [Citation(s) in RCA: 94] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
STUDY OBJECTIVES We analyzed the potential predictive factors for precocious puberty, observed in some cases of childhood narcolepsy with cataplexy (NC) and for obesity, a much more common feature of NC, through a systematic assessment of pubertal staging, body mass index (BMI), and metabolic/endocrine biochemical analyses. DESIGN Cross-sectional on consecutive recruitment. SETTING Hospital sleep center and pediatric unit. PATIENTS Forty-three children and adolescents with NC versus 52 age-matched obese children as controls. INTERVENTIONS N/A. MEASUREMENTS AND RESULTS Patients underwent clinical interview, polysomnographic recordings, cerebrospinal fluid hypocretin-1 measurement, and human leukocyte antigen typing. Height, weight, arterial blood pressure, and Tanner pubertal stage were evaluated. Plasma lipid and glucose profiles were analyzed. When an altered pubertal development was clinically suspected, plasma concentrations of hypothalamic-pituitary-gonadal axis hormones were determined. Children with NC showed a high prevalence of overweight/obesity (74%) and a higher occurrence of precocious puberty (17%) than obese controls (1.9%). Isolated signs of accelerated pubertal development (thelarche, pubic hair, advanced bone age) were also present (41%). Precocious puberty was significantly predicted by a younger age at first NC symptom onset but not by overweight/obesity or other factors. In addition, overweight/obesity was predicted by younger age at diagnosis; additional predictors were found for overweight/obesity (short disease duration, younger age at weight gain and lower high-density lipoprotein cholesterol), which did not include precocious puberty. NC symptoms, pubertal signs appearance, and body weight gain developed in close temporal sequence. CONCLUSIONS NC occurring during prepubertal age is frequently accompanied by precocious puberty and overweight/obesity, suggesting an extended hypothalamic dysfunction. The severity of these comorbidities and the potential related risks require a multidiagnostic approach and a tailored therapeutic management.
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Affiliation(s)
- Francesca Poli
- Department of Neurological Sciences, University of Bologna - IRCCS Istituto delle Scienze Neurologiche di Bologna, Bologna, Italy
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Zhang XY, Yu L, Zhuang QX, Zhu JN, Wang JJ. Central functions of the orexinergic system. Neurosci Bull 2013; 29:355-65. [PMID: 23299718 DOI: 10.1007/s12264-012-1297-4] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2012] [Accepted: 07/18/2012] [Indexed: 10/27/2022] Open
Abstract
The neuropeptide orexin is synthesized by neurons exclusively located in the hypothalamus. However, these neurons send axons over virtually the entire brain and spinal cord and therefore constitute a unique central orexinergic system. It is well known that central orexin plays a crucial role in the regulation of various basic non-somatic and somatic physiological functions, including feeding, energy homeostasis, the sleep/wake cycle, reward, addiction, and neuroendocrine, as well as motor control. Moreover, the absence of orexin results in narcolepsy-cataplexy, a simultaneous somatic and non-somatic dysfunction. In this review, we summarize these central functions of the orexinergic system and associated diseases, and suggest that this system may hold a key position in somatic-non-somatic integration.
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Affiliation(s)
- Xiao-Yang Zhang
- Department of Biological Science and Technology and State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing, 210093, China
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Gómez-González B, Domínguez-Salazar E, Hurtado-Alvarado G, Esqueda-Leon E, Santana-Miranda R, Rojas-Zamorano JA, Velázquez-Moctezuma J. Role of sleep in the regulation of the immune system and the pituitary hormones. Ann N Y Acad Sci 2012; 1261:97-106. [PMID: 22823399 DOI: 10.1111/j.1749-6632.2012.06616.x] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Sleep is characterized by a reduced response to external stimuli and a particular form of electroencephalographic (EEG) activity. Sleep is divided into two stages: REM sleep, characterized by muscle atonia, rapid eye movements, and EEG activity similar to wakefulness, and non-REM sleep, characterized by slow EEG activity. Around 80% of total sleep time is non-REM. Although it has been intensely studied for decades, the function (or functions) of sleep remains elusive. Sleep is a highly regulated state; some brain regions and several hormones and cytokines participate in sleep regulation. This mini-review focuses on how pituitary hormones and cytokines regulate or affect sleep and how sleep modifies the plasma concentration of hormones as well as cytokines. Also, we review the effects of hypophysectomy and some autoimmune diseases on sleep pattern. Finally, we propose that one of the functions of sleep is to maintain the integrity of the neuro-immune-endocrine system.
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Affiliation(s)
- Beatriz Gómez-González
- Department of Biology of Reproduction and Sleep Disorders Clinic, Universidad Autónoma Metropolitana-Iztapalapa, Mexico City, Federal District, Mexico
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Abstract
Orexin receptors type 1 (OX1R) and type 2 (OX2R) are G protein-coupled receptors whose structure is highly conserved in mammals. OX1R is selective for orexin A, and OX2R binds orexin A and orexin B with similar affinity. Orexin receptor expression was observed in human, rat, porcine, sheep as well as Xenopus laevis pituitaries, both in the adenohypophysis and in the neurohypophysis. The expression level is regulated by gonadal steroid hormones and GnRH. The majority of orexins reaching the pituitary originate from the lateral hypothalamus, but due to the presence of the receptors and the local production of orexins in the pituitary, orexins could deliver an auto/paracrine effect within the gland. Cumulative data indicate that orexins are involved in the regulation of LH, GH, PRL, ACTH, and TSH secretion by pituitary cells, pointing to orexins' effect on the functioning of the endocrine axes. Those hormones may also serve as a signal linking metabolic status with endocrine control of sleep, arousal, and reproduction processes.
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Affiliation(s)
- Tadeusz Kaminski
- Department of Animal Physiology, University of Warmia and Mazury in Olsztyn, Olsztyn-Kortowo, Poland
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23
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Nitkiewicz A, Smolinska N, Przala J, Kaminski T. Expression of orexin receptors 1 (OX1R) and 2 (OX2R) in the porcine ovary during the oestrous cycle. ACTA ACUST UNITED AC 2010; 165:186-90. [DOI: 10.1016/j.regpep.2010.07.166] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2009] [Revised: 07/16/2010] [Accepted: 07/26/2010] [Indexed: 01/09/2023]
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NING HM, GE YM, SU J, ZHANG WL, YAO Y, YANG GH, LEI ZH. Effects of Orexin A on mRNA Expression of Various Neuropeptides in the Hypothalamus and Pituitary, and on Serum LH Levels in Ovariectomized Gilts. ACTA ACUST UNITED AC 2010. [DOI: 10.1016/s1671-2927(09)60227-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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López M, Tena-Sempere M, Diéguez C. Cross-talk between orexins (hypocretins) and the neuroendocrine axes (hypothalamic-pituitary axes). Front Neuroendocrinol 2010; 31:113-27. [PMID: 19654017 DOI: 10.1016/j.yfrne.2009.07.001] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/17/2008] [Revised: 07/28/2009] [Accepted: 07/29/2009] [Indexed: 02/06/2023]
Abstract
Lesioning and electrical stimulation experiments carried out during the first half of the twentieth century showed that the lateral hypothalamic area (LHA) is involved in the neuroendocrine control of hormone secretion. However, the molecular basis of this phenomenon remained unclear until fifty years later when in 1998, two different laboratories discovered a new family of hypothalamic neuropeptides, the orexins or hypocretins (OX-A/Hcrt1 and OX-B/Hcrt2). Since then, remarkable evidence has revealed that orexins/hypocretins play a prominent role in regulating virtually all the neuroendocrine axes, acting as pivotal signals in the coordination of endocrine responses with regards to sleep, arousal and energy homeostasis. The clinical relevance of these actions is supported by human data showing impairment of virtually all the neuroendocrine axes in orexin/hypocretin-deficient narcoleptic patients. Here, we summarize more than ten years of knowledge about the orexins/hypocretins with particular focus on their role as neuroendocrine regulators. Understanding this aspect of orexin/hypocretin physiology could open new therapeutic possibilities in the treatment of sleep, energy homeostasis and endocrine pathologies.
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Affiliation(s)
- Miguel López
- Department of Physiology, School of Medicine, University of Santiago de Compostela - Instituto de Investigación Sanitaria, Santiago de Compostela 15782, Spain.
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Abstract
Orexins (OX), OX-A and OX-B, were initially identified as hypothalamic neuropeptides primarily involved in the control of food intake and states of arousal. Thereafter, orexins have been substantiated as putative pleiotropic regulators of a wide diversity of biological systems, including different neuroendocrine axes. Among the latter, compelling experimental evidence has recently been documented that orexins, mainly OX-A, may act at different levels of the hypothalamic-pituitary-gonadal (HPG) axis to modulate reproductive function. These actions are likely to include regulatory effects on the hypothalamic centres governing the HPG axis, as well as direct actions at the gonadal level. We review herein the experimental evidence, gathered in recent years, supporting a reproductive 'facet' of orexins, with special emphasis on our current knowledge of their patterns of expression and potential functional roles in the testis. Overall, the available data strongly suggest that, by acting at different levels of the HPG axis, orexins may operate as putative neuroendocrine and autocrine/paracrine regulators of gonadal function.
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Affiliation(s)
- M Nurmio
- Department of Physiology, University of Turku, Turku, Finland
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Smilde AK, Westerhuis JA, Hoefsloot HCJ, Bijlsma S, Rubingh CM, Vis DJ, Jellema RH, Pijl H, Roelfsema F, van der Greef J. Dynamic metabolomic data analysis: a tutorial review. Metabolomics 2010; 6:3-17. [PMID: 20339444 PMCID: PMC2834778 DOI: 10.1007/s11306-009-0191-1] [Citation(s) in RCA: 90] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/28/2009] [Accepted: 11/09/2009] [Indexed: 12/23/2022]
Abstract
In metabolomics, time-resolved, dynamic or temporal data is more and more collected. The number of methods to analyze such data, however, is very limited and in most cases the dynamic nature of the data is not even taken into account. This paper reviews current methods in use for analyzing dynamic metabolomic data. Moreover, some methods from other fields of science that may be of use to analyze such dynamic metabolomics data are described in some detail. The methods are put in a general framework after providing a formal definition on what constitutes a 'dynamic' method. Some of the methods are illustrated with real-life metabolomics examples.
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Affiliation(s)
- A. K. Smilde
- Biosystems Data Analysis, Swammerdam Institute for LifeSciences, University of Amsterdam, Nieuwe Achtergracht 166, 1018 WV Amsterdam, The Netherlands
| | - J. A. Westerhuis
- Biosystems Data Analysis, Swammerdam Institute for LifeSciences, University of Amsterdam, Nieuwe Achtergracht 166, 1018 WV Amsterdam, The Netherlands
| | - H. C. J. Hoefsloot
- Biosystems Data Analysis, Swammerdam Institute for LifeSciences, University of Amsterdam, Nieuwe Achtergracht 166, 1018 WV Amsterdam, The Netherlands
| | - S. Bijlsma
- TNO Quality of Life, Utrechtseweg 48, 3704 HE Zeist, TheNetherlands
| | - C. M. Rubingh
- TNO Quality of Life, Utrechtseweg 48, 3704 HE Zeist, TheNetherlands
| | - D. J. Vis
- Biosystems Data Analysis, Swammerdam Institute for LifeSciences, University of Amsterdam, Nieuwe Achtergracht 166, 1018 WV Amsterdam, The Netherlands
| | - R. H. Jellema
- TNO Quality of Life, Utrechtseweg 48, 3704 HE Zeist, TheNetherlands
| | - H. Pijl
- Department of Endocrinology and Metabolic Diseases, Leiden University Medical Center, Leiden, The Netherlands
| | - F. Roelfsema
- Department of Endocrinology and Metabolic Diseases, Leiden University Medical Center, Leiden, The Netherlands
| | - J. van der Greef
- TNO Quality of Life, Utrechtseweg 48, 3704 HE Zeist, TheNetherlands
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Perriol MP, Cartigny M, Lamblin MD, Poirot I, Weill J, Derambure P, Monaca C. Childhood-onset narcolepsy, obesity and puberty in four consecutive children: a close temporal link. J Pediatr Endocrinol Metab 2010; 23:257-65. [PMID: 20480724 DOI: 10.1515/jpem.2010.23.3.257] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Narcolepsy is a rare but disabling condition that causes excessive daytime sleepiness. Interestingly, weight gain is frequent in patients with narcolepsy and it has sometimes been described very early in the course of the disease. Here, we report four consecutive obese children who were referred to our sleep laboratory for excessive daytime sleepiness and suspected sleep apnoea syndrome. They underwent nocturnal polysomnography associated with multiple sleep latency tests. Narcolepsy was diagnosed in all children with a close temporal link between the onset of narcolepsy, obesity and puberty. Scientifically, the relationship between sleep, weight, growth rate and puberty onset is striking and merits further investigation. From the clinical point of view, narcolepsy must be investigated in obese sleepy children along with obstructive sleep apnoea. Indeed, it can be controlled with appropriate treatment but the proper diagnosis relies not only upon nocturnal polysomnography but involves the systematic use of multiple sleep latency tests.
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Affiliation(s)
- M-P Perriol
- Neurophysiologie Clinique, Lille University Hospital, Lille, France.
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Abstract
Appropriate nutritional and vigilance states are needed for reproduction. In previous works, we described the influence of the hormonal milieu of proestrus on the orexinergic system and we found that orexin receptor 1 expression in the hypothalamus, but not other neural areas, and the adenohypophysis was under the influence of oestradiol and the time of the day. Information from the sexual hormonal milieu of proestrous afternoon impacts on various components of the orexinergic system and alertness on this particular night of proestrus would be of importance for successful reproduction. In this review, we summarize the available experimental data supporting the participation of orexins in the hypothalamic-pituitary-ovarian relationships. All together, these results suggest a role of the orexinergic system as an integrative link among vital functions such as reproduction, food intake, alertness and the inner biological clock.
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Affiliation(s)
- P Silveyra
- Instituto de Biología y Medicina Experimental-CONICET, Buenos Aires, Argentina
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Vis DJ, Westerhuis JA, Hoefsloot HCJ, Pijl H, Roelfsema F, van der Greef J, Smilde AK. Endocrine pulse identification using penalized methods and a minimum set of assumptions. Am J Physiol Endocrinol Metab 2010; 298:E146-55. [PMID: 19861586 DOI: 10.1152/ajpendo.00048.2009] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The detection of hormone secretion episodes is important for understanding normal and abnormal endocrine functioning, but pulse identification from hormones measured with short interval sampling is challenging. Furthermore, to obtain useable results, the model underlying hormone secretion and clearance must be augmented with restrictions based on biologically acceptable assumptions. Here, using the assumption that there are only a few time points at which a hormone is secreted, we used a modern penalized nonlinear least-squares setup to select the number of secretion events. We did not assume a particular shape or frequency distribution for the secretion pulses. Our pulse identfication method, VisPulse, worked well with luteinizing hormone (LH), cortisol, growth hormone, or testosterone. In particular, applying our modeling strategy to previous LH data revealed a good correlation between the modeled and measured LH hormone concentrations, the estimated secretion pattern was sparse, and the small and structureless residuals indicated a proper model with a good fit. We benchmarked our method to AutoDecon, a commonly used hormone secretion model, and performed releasing hormone infusion experiments. The results of these experiments confirmed that our method is accurate and outperforms AutoDecon, especially for detecting silent periods and small secretion events, suggesting a high-secretion event resolution. Method validation using (releasing hormone) infusion data revealed sensitivities and selectivities of 0.88 and 0.95 and of 0.69 and 0.91 for VisPulse and AutoDecon, respectively.
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Affiliation(s)
- Daniel J Vis
- BioSystems Data Analysis group, Swammerdam Institute for Life Science, Univ. of Amsterdam, Nieuwe Achtergracht 166, Amsterdam 1018 WV, The Netherlands
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Kaminski T, Smolinska N, Nitkiewicz A, Przala J. Expression of orexin receptors 1 (OX1R) and 2 (OX2R) in the porcine pituitary during the oestrous cycle. Anim Reprod Sci 2010; 117:111-8. [DOI: 10.1016/j.anireprosci.2009.03.007] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2008] [Revised: 02/12/2009] [Accepted: 03/17/2009] [Indexed: 10/21/2022]
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Silveyra P, Cataldi NI, Lux-Lantos V, Libertun C. Gonadal steroids modulated hypocretin/orexin type-1 receptor expression in a brain region, sex and daytime specific manner. ACTA ACUST UNITED AC 2009; 158:121-6. [PMID: 19699765 DOI: 10.1016/j.regpep.2009.08.002] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2009] [Revised: 07/28/2009] [Accepted: 08/12/2009] [Indexed: 11/26/2022]
Abstract
Orexins A and B (hypocretins A and B) are regulatory peptides that control a variety of neuroendocrine and autonomic functions including feeding and sleep-wakefulness. Previously, we described a clear relationship between the hormonal milieu of the estrous cycle and the mRNA expression of the components of the orexinergic system, in the hypothalamus, pituitary and ovary. Here, we investigate whether steroid hormones are involved in the modulation of the hypocretin/orexin type-1 receptor expression at the protein level, and its time of the day dependence, in hypothalamus and pituitary of castrated male and female rats and castrated receiving hormone replacement. Orchidectomy decreased the hypocretin/orexin type-1 receptor expression in anterior hypothalamus, but not in mediobasal hypothalamus or cortex; in pituitary this treatment resulted in an increase. Testosterone and dihydrotestosterone were able to restore receptor expression and gonadotropins. In females, pituitary and ovarian hormones increased during proestrous afternoon. Hypocretin/orexin type-1 receptor expression was higher at 19:00 of proestrus in hypothalamus and pituitary. Ovariectomized treated with estradiol or oil and sacrificed at 11:00 h showed the receptor expression similar to 11:00 h of proestrus in hypothalamus and pituitary. At 19:00 h, low expression persisted in these areas in oil-treated ovariectomized rats; in contrast, estradiol replacement increased the expression to high levels of normal cycling rats at 19:00 h. Sexual steroids modulate the orexinergic system and the anatomical regions, hormones and times of the day all have to be considered when the roles of orexins, and probably other peptides, are under consideration.
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Evaul K, Hammes SR. Cross-talk between G protein-coupled and epidermal growth factor receptors regulates gonadotropin-mediated steroidogenesis in Leydig cells. J Biol Chem 2008; 283:27525-27533. [PMID: 18701461 DOI: 10.1074/jbc.m803867200] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Gonadal steroid production is stimulated by gonadotropin binding to G protein-coupled receptors (GPCRs). Although GPCR-mediated increases in intracellular cAMP are known regulators of steroidogenesis, the roles of other signaling pathways in mediating steroid production are not well characterized. Recent studies suggest that luteinizing hormone (LH) receptor activation leads to trans-activation of epidermal growth factor (EGF) receptors in the testes and ovary. This pathway is critical for LH-induced steroid production in ovarian follicles, probably through matrix metalloproteinase (MMP)-mediated release of EGF receptor (EGFR) binding ectodomains. Here we examined LH and EGF receptor cross-talk in testicular steroidogenesis using mouse MLTC-1 Leydig cells. We demonstrated that, similar to the ovary, trans-activation of the EGF receptor was critical for gonadotropin-induced steroid production in Leydig cells. LH-induced increases in cAMP and cAMP-dependent protein kinase (PKA) activity mediated trans-activation of the EGF receptor and subsequent mitogen-activated protein kinase (MAPK) activation, ultimately leading to StAR phosphorylation and mitochondrial translocation. Steroidogenesis in Leydig cells was unaffected by MMP inhibitors, suggesting that cAMP and PKA trans-activated EGF receptors in an intracellular fashion. Interestingly, although cAMP was always needed for steroidogenesis, the EGFR/MAPK pathway was activated and necessary only for early (30-60 min), but not late (120 min or more), LH-induced steroidogenesis in vitro. In contrast, 36-h EGF receptor inhibition in vivo significantly reduced serum testosterone levels in male mice, demonstrating the physiologic importance of this cross-talk. These results suggest that GPCR-EGF receptor cross-talk is a conserved regulator of gonadotropin-induced steroidogenesis in the gonads, although the mechanisms of EGF receptor trans-activation may vary.
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Affiliation(s)
- Kristen Evaul
- Departments of Internal Medicine and Pharmacology, University of Texas Southwestern Medical Center, Dallas, Texas 75390
| | - Stephen R Hammes
- Departments of Internal Medicine and Pharmacology, University of Texas Southwestern Medical Center, Dallas, Texas 75390.
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Hoskins LJ, Xu M, Volkoff H. Interactions between gonadotropin-releasing hormone (GnRH) and orexin in the regulation of feeding and reproduction in goldfish (Carassius auratus). Horm Behav 2008; 54:379-85. [PMID: 18544455 DOI: 10.1016/j.yhbeh.2008.04.011] [Citation(s) in RCA: 86] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/22/2008] [Revised: 04/23/2008] [Accepted: 04/28/2008] [Indexed: 11/25/2022]
Abstract
Links between energy homeostasis and reproduction have been demonstrated in vertebrates. As a general rule, abundant food resources favor reproduction whereas low food availability induces an inhibition of reproductive processes. In both mammals and fish, gonadotropin-releasing hormone (GnRH) and orexin (OX) are hypothalamic neuropeptides that play critical roles in the regulation of sexual behavior and appetite, respectively. In order to assess possible interactions between orexin and GnRH in the control of feeding and reproduction in goldfish, we examined the effects of chicken GnRH (cGnRH-II) intracerebroventricular (ICV) injection on feeding behavior and OX brain mRNA expression as well as the effects of orexin ICV injections on spawning behavior and cGnRH-II brain mRNA expression. Treatment with cGnRH-II at doses that stimulate spawning (0.5 ng/g or 1 ng/g) resulted in a decrease in both food intake and hypothalamic orexin mRNA expression. Treatment with orexin A at doses that stimulate feeding (10 ng/g) induced an inhibition of spawning behavior and a decrease in cGnRH-II expression in the hypothalamus and optic tectum-thalamus. Our results suggest that the anorexigenic actions of cGnRH-II in goldfish might be in part mediated by OX and that orexin inhibits reproductive behavior in part via the inhibition of the GnRH system. Our data suggest the existence of a coordinated control of feeding and reproduction by the orexin and GnRH systems in goldfish.
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Affiliation(s)
- Leah J Hoskins
- Department of Biology, Memorial University of Newfoundland, St. John's, NL, Canada A1B 3X9
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Abstract
Reproduction is a physiologically costly process that consumes significant amounts of energy. The physiological mechanisms controlling energy balance are closely linked to fertility. This close relationship ensures that pregnancy and lactation occur only in favourable conditions with respect to energy. The primary metabolic cue that modulates reproduction is the availability of oxidizable fuel. An organism's metabolic status is transmitted to the brain through metabolic fuel detectors. There are many of these detectors at both the peripheral (e.g., leptin, insulin, ghrelin) and central (e.g., neuropeptide Y, melanocortin, orexins) levels. When oxidizable fuel is scarce, the detectors function to inhibit the release of gonadotropin-releasing hormone and luteinizing hormone, thereby altering steroidogenesis, reproductive cyclicity, and sexual behaviour. Infertility can also result when resources are abundant but food intake fails to compensate for increased energy demands. Examples of these conditions in women include anorexia nervosa and exercise-induced amenorrhea. Infertility associated with obesity appears to be less related to an effect of oxidizable fuel on the hypothalamic-pituitary-ovarian axis. Impaired insulin sensitivity may play a role in the etiology of these conditions, but their specific etiology remains unresolved. Research into the metabolic regulation of reproductive function has implications for elucidating mechanisms of impaired pubertal development, nutritional amenorrhea, and obesity-related infertility. A better understanding of these etiologies has far-reaching implications for the prevention and management of reproductive dysfunction and its associated comorbidities.
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Affiliation(s)
- Carmen N Mircea
- Department of Obstetrics, Gynecology and Reproductive Sciences, College of Medicine, University of Saskatchewan Saskatoon SK
| | - Marla E Lujan
- Department of Obstetrics, Gynecology and Reproductive Sciences, College of Medicine, University of Saskatchewan Saskatoon SK
| | - Roger A Pierson
- Department of Obstetrics, Gynecology and Reproductive Sciences, College of Medicine, University of Saskatchewan Saskatoon SK
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Silveyra P, Lux-Lantos V, Libertun C. Both orexin receptors are expressed in rat ovaries and fluctuate with the estrous cycle: effects of orexin receptor antagonists on gonadotropins and ovulation. Am J Physiol Endocrinol Metab 2007; 293:E977-85. [PMID: 17638707 DOI: 10.1152/ajpendo.00179.2007] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Orexins are peptides controlling feeding, sleep, and neuroendocrine functions. They are synthesized by the hypothalamus with projections throughout the brain. Orexins and their orexin 1 (OX(1)) and orexin 2 receptors (OX(2)) are present outside the central nervous system. Here the expression of preproorexin (PPO), OX(1), and OX(2) was studied in rat ovaries. PPO, OX(1), and OX(2) were determined by quantitative real-time RT-PCR in ovaries of cycling Sprague-Dawley rats on all days of the cycle. Serum hormones and food consumption were determined. Ovarian OX(1) and OX(2) expression was then studied after ovulation blockade with Cetrorelix or Nembutal. Finally, proestrous rats were treated at 1400 and 1900 with a selective OX(1) antagonist (SB-334867-A) and/or a selective OX(2) antagonist (JNJ-10397049), and hormone levels, ovulation, and ovarian histology were studied. Both receptors' expression increased in the ovary between 1700 and 2300 of proestrus exclusively, in coincidence with hormone peaks, but not with the dark-light cycle or food intake. PPO was not detected. Cetrorelix or Nembutal prevented the increases of OX(1) and OX(2) while blunting gonadotropin peaks. SB-334867-A and JNJ-10397049, alone or combined, decreased serum gonadotropins and reduced ova number the following morning; ovaries showed a bloody (hyperemic and/or hemorrhagic) reaction with more preovulatory follicles and less corpora lutea. Here we demonstrate for the first time an increased ovarian expression of both OX(1) and OX(2), only during proestrous afternoon, and its hormone dependence but not dependence on the dark-light cycle. Two new receptor antagonists reduced proestrous gonadotropins and/or ova number while producing ovarian structural changes.
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Affiliation(s)
- Patricia Silveyra
- Instituto de Biología y Medicina Experimental-Consejo Nacional de Investigaciones Científicas y Técnicas, Universidad de Buenos Aires, Argentina
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37
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Silveyra P, Catalano PN, Lux-Lantos V, Libertun C. Impact of proestrous milieu on expression of orexin receptors and prepro-orexin in rat hypothalamus and hypophysis: actions of Cetrorelix and Nembutal. Am J Physiol Endocrinol Metab 2007; 292:E820-8. [PMID: 17122088 DOI: 10.1152/ajpendo.00467.2006] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Orexins and their receptors OX1 and OX2 regulate energy balance and the sleep-wake cycle. We studied the expression of prepro-orexin (PPO), OX1, and OX2 in brain and pituitary under the influence of the hormonal status in adult rats. Primarily, PPO, OX1, and OX2 expression was determined in Sprague-Dawley female cycling rats during proestrus and in males. Animals were killed at 2-h intervals. Anterior (AH) and mediobasal (MBH) hypothalamus, anterior pituitary (P), and frontoparietal cortex (CC) were homogenized in TRIzol, and mRNAs were obtained for screening of PPO, OX1, OX2 expression by semiquantitative RT-PCR. Main findings were confirmed and extended to all days of the cycle by quantitative real-time RT-PCR. Hormones and food consumption were determined. Finally, OX1, OX2, and PPO were measured by real-time RT-PCR in tissues collected at 1900 of proestrus after treatments at 1400 with ovulation-blocking agents Cetrorelix or pentobarbital. OX1 and OX2 expression increased at least threefold in AH, MBH, and P, but not in CC, between 1700 and 2300 of proestrus, without variations in estrus, diestrus, or in males. PPO in AH and MBH showed a fourfold or higher increase only during proestrus afternoon. Cetrorelix or pentobarbital prevented increases of OX1 and OX2 only in the pituitary and blunted gonadotropin surges, but left OX1, OX2, and PPO brain expression unchanged. Reproduction, energy balance, and sleep-wake cycle are integrated. Here, we demonstrate that, in the physiological neuroendocrine condition leading to ovulation, information to the orexinergic system acts in hypothalamus and pituitary by different mechanisms.
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Affiliation(s)
- Patricia Silveyra
- Instituto de Biología y Medicina Experimental, Consejo Nacional de Investigaciones Cientificas y Técnicas, Buenos Aires, Argentina
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38
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Abstract
Hypothalamic excitatory hypocretin (orexin) neurons have been discovered in 1998 and found to have widespread projections to basal forebrain, monoaminergic and cholinergic brainstem, and spinal cord regions. The hypocretin system is influenced both neuronally (e.g. suprachiasmatic nucleus, GABAergic, cholinergic and aminergic brainstem nuclei) as well as metabolically (e.g. glucose, ghrelin, and leptin). Physiologically the hypocretin system has been implicated in the regulation of behaviours that are associated with wakefulness, locomotion, and feeding. A role in REM sleep, neuroendocrine, autonomic and metabolic functions has also been suggested. Pathophysiologically a deficient hypocretin neurotransmission has been found in human narcolepsy and (engineered) animal models of the disorder. Different mechanisms are involved including (1) degeneration of hypocretin neurons (mice), (2) hypocretin ligand deficiency (humans, mice, dogs), (3) hypocretin receptor deficiency (mice, dogs). Reports of low hypocretin-1 cerebrospinal fluid levels in neurologic conditions (e.g. Guillain-Barré syndrome, traumatic brain injury, hypothalamic lesions) with and without sleep-wake disturbances and, on the other hand, observations of normal levels in about 11% of narcoleptics raise questions about the exact nature and pathophysiological base of the link between hypocretin deficiency and clinical manifestations in human narcolepsy.
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Affiliation(s)
- Christian R Baumann
- Neurologische Klinik, Universitätsspital Zürich, Frauenklinikstrasse 26, CH-8091 Zürich, Switzerland
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