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de Paula DG, Bohlen TM, Zampieri TT, Mansano NS, Vieira HR, Gusmao DO, Wasinski F, Donato J, Frazao R. Distinct effects of growth hormone deficiency and disruption of hypothalamic kisspeptin system on reproduction of male mice. Life Sci 2021; 285:119970. [PMID: 34562435 DOI: 10.1016/j.lfs.2021.119970] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2021] [Revised: 09/08/2021] [Accepted: 09/16/2021] [Indexed: 12/30/2022]
Abstract
Growth hormone (GH) deficiency is a common cause of late sexual maturation and fertility issues. To determine whether GH-induced effects on reproduction are associated with alterations in hypothalamic kisspeptin system, we studied the male reproduction in two distinct GH deficiency mouse models. In the first model, mice present GH deficiency secondary to arcuate nucleus of the hypothalamus (ARH) lesions induced by posnatal monosodium glutamate (MSG) injections. MSG-induced ARH lesions led to significant reductions in hypothalamic Ghrh mRNA expression and consequently growth. Hypothalamic Kiss1 mRNA expression and Kiss1-expressing cells in the ARH were disrupted in the MSG-treated mice. In contrast, kisspeptin immunoreactivity remained preserved in the anteroventral periventricular and rostral periventricular nuclei (AVPV/PeN) of MSG-treated mice. Importantly, ARH lesions caused late sexual maturation and infertility in male mice. In our second mouse model, we studied animals profound GH deficiency due to a loss-of-function mutation in the Ghrhr gene (Ghrhrlit/lit mice). Interestingly, although Ghrhrlit/lit mice exhibited late puberty onset, hypothalamic Kiss1 mRNA expression and hypothalamic kisspeptin fiber density were normal in Ghrhrlit/lit mice. Despite presenting dwarfism, the majority of Ghrhrlit/lit male mice were fertile. These findings suggest that spontaneous GH deficiency during development does not compromise the kisspeptin system. Furthermore, ARH Kiss1-expressing neurons are required for fertility, while AVPV/PeN kisspeptin expression is sufficient to allow maturation of the hypothalamic-pituitary-gonadal axis in male mice.
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Affiliation(s)
- Daniella G de Paula
- Department of Anatomy, Institute of Biomedical Sciences, University of São Paulo, São Paulo, SP, Brazil
| | - Tabata M Bohlen
- Department of Anatomy, Institute of Biomedical Sciences, University of São Paulo, São Paulo, SP, Brazil
| | - Thais Tessari Zampieri
- Department of Anatomy, Institute of Biomedical Sciences, University of São Paulo, São Paulo, SP, Brazil
| | - Naira S Mansano
- Department of Anatomy, Institute of Biomedical Sciences, University of São Paulo, São Paulo, SP, Brazil
| | - Henrique R Vieira
- Department of Anatomy, Institute of Biomedical Sciences, University of São Paulo, São Paulo, SP, Brazil
| | - Daniela O Gusmao
- Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of São Paulo, São Paulo, SP, Brazil
| | - Frederick Wasinski
- Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of São Paulo, São Paulo, SP, Brazil
| | - Jose Donato
- Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of São Paulo, São Paulo, SP, Brazil
| | - Renata Frazao
- Department of Anatomy, Institute of Biomedical Sciences, University of São Paulo, São Paulo, SP, Brazil.
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Pimenta FDS, Tose H, Waichert É, da Cunha MRH, Campos FV, Vasquez EC, Mauad H. Lipectomy associated to obesity produces greater fat accumulation in the visceral white adipose tissue of female compared to male rats. Lipids Health Dis 2019; 18:44. [PMID: 30738429 PMCID: PMC6368803 DOI: 10.1186/s12944-019-0988-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2018] [Accepted: 01/24/2019] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Mobility of fat deposited in adipocytes among different fatty territories can play a crucial role in the pathogenesis of obesity-related diseases. Our goal was to investigate which of the remaining fat pads assume the role of accumulating lipids after surgical removal of parietal WAT (lipectomy; LIPEC) in rats of both sexes displaying MSG-induced obesity. METHODS The animals entered the study straight after birth, being separated according to gender and randomly divided into CON (control, saline-treated) and MSG (monosodium glutamate-treated) groups. Next, the animals underwent LIPEC or sham-operated surgery (SHAM). Obesity was induced by the injection of MSG (4 mg/g/day) during neonatal stage (2nd to 11th day from birth). LIPEC was performed on the 12th week, consisting in the withdrawal of parietal WAT. On the 16th week, the following WATs were isolated and collected: peri-epididymal-WAT (EP-WAT); parametrial-WAT (PM-WAT); omental-WAT (OM-WAT); perirenal-WAT (PR-WAT) and retroperitoneal-WAT (RP-WAT). RESULTS The adiposity index was significantly increased in both male (3.2 ± 0.2** vs 1.8 ± 0.1) and female (4.9 ± 0.7* vs 2.6 ± 0.3) obese rats compared to their respective control groups. LIPEC in obese animals produced fat accumulation in visceral fat sites in a more accentuated manner in female (3.6 ± 0.3** vs 2.8 ± 0.3 g/100 g) rather than in male (1.8 ± 0.2* vs 1.5 ± 0.1 g/100 g) rats compared to obese non-lipectomized animals. Among the visceral WATs, the greater differences were observed between gonadal WATs of obese lipectomized rats, with higher accumulation having been observed in PM-WAT (2.8 ± 0.3* vs 2.1 ± 0.2 g/100 g) rather than in EP-WAT (1.0 ± 0.1 ± 0.9 ± 0.1 g/100 g) when compared to obese non-lipectomized animals. CONCLUSIONS The results of the present study led us to conclude that obesity induced by MSG treatment occurs differently in male and female rats. When associated with parietal LIPEC, there was a significant increase in the deposition of visceral fat, which was significantly higher in obese female rats than in males, indicating that fat mobility among WATs in lipectomized-obese rats can occur more expressively in particular sites of remaining WATs.
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Affiliation(s)
- Fábio da Silva Pimenta
- Laboratory of Translational Physiology and Pharmacology, Pharmaceutical Sciences Graduate Program, Vila Velha University (UVV), Avenida Comissário José Dantas de Melo, 21 Bairro Boa Vista II, Vila Velha, ES, CEP 29102-920, Brazil
| | - Hadnan Tose
- Departament of Medical Clinic, Escola Superior de Ciências da Santa Casa de Misericórdia de Vitória (EMESCAM), Av. Nossa Sra. da Penha, 2190 - Bela Vista, Vitória, ES, CEP 29027-502, Brazil
| | - Élio Waichert
- Faculdade Estácio, Av. Dr. Herwan Modenese Wanderley, 1001. Bairro Jardim Camburi, Vitória, ES, CEP 29092-095, Brazil
| | - Márcia Regina Holanda da Cunha
- Sports Department, Center for Physical Education and Sports, Federal University of Espírito Santo, Avenida Fernando Ferrari, 514. Bairro Goiabeiras, Vitória, ES, CEP 29075-910, Brazil
| | - Fabiana Vasconcelos Campos
- Department of Physiological Sciences, Health Sciences Center, Federal University of Espírito Santo, Av. Marechal Campos 1468, Vitória, ES, CEP 29042-751, Brazil
| | - Elisardo Corral Vasquez
- Laboratory of Translational Physiology and Pharmacology, Pharmaceutical Sciences Graduate Program, Vila Velha University (UVV), Avenida Comissário José Dantas de Melo, 21 Bairro Boa Vista II, Vila Velha, ES, CEP 29102-920, Brazil
| | - Hélder Mauad
- Department of Physiological Sciences, Health Sciences Center, Federal University of Espírito Santo, Av. Marechal Campos 1468, Vitória, ES, CEP 29042-751, Brazil.
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Gasem MAT. Effect of monosodium glutamate and aspartame on behavioral and biochemical parameters of male albino mice. ACTA ACUST UNITED AC 2016. [DOI: 10.5897/ajb2015.15199] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
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Sasaki-Hamada S, Hojo Y, Koyama H, Otsuka H, Oka JI. Changes in hippocampal synaptic functions and protein expression in monosodium glutamate-treated obese mice during development of glucose intolerance. Eur J Neurosci 2015; 41:1393-401. [DOI: 10.1111/ejn.12891] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2014] [Revised: 02/22/2015] [Accepted: 03/09/2015] [Indexed: 01/25/2023]
Affiliation(s)
- Sachie Sasaki-Hamada
- Laboratory of Pharmacology; Faculty of Pharmaceutical Sciences; Tokyo University of Science; 2641 Yamazaki Noda Chiba 278-8510 Japan
| | - Yuki Hojo
- Laboratory of Pharmacology; Faculty of Pharmaceutical Sciences; Tokyo University of Science; 2641 Yamazaki Noda Chiba 278-8510 Japan
| | - Hajime Koyama
- Laboratory of Pharmacology; Faculty of Pharmaceutical Sciences; Tokyo University of Science; 2641 Yamazaki Noda Chiba 278-8510 Japan
| | - Hayuma Otsuka
- Laboratory of Pharmacology; Faculty of Pharmaceutical Sciences; Tokyo University of Science; 2641 Yamazaki Noda Chiba 278-8510 Japan
| | - Jun-Ichiro Oka
- Laboratory of Pharmacology; Faculty of Pharmaceutical Sciences; Tokyo University of Science; 2641 Yamazaki Noda Chiba 278-8510 Japan
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Saderi N, Buijs F, Salgado-Delgado R, Merkenstein M, Basualdo M, Ferri GL, Escobar C, Buijs R. A role for VGF in the hypothalamic arcuate and paraventricular nuclei in the control of energy homeostasis. Neuroscience 2014; 265:184-95. [DOI: 10.1016/j.neuroscience.2014.01.060] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2013] [Revised: 01/27/2014] [Accepted: 01/29/2014] [Indexed: 10/25/2022]
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Davalli AM, Perego C, Folli FB. The potential role of glutamate in the current diabetes epidemic. Acta Diabetol 2012; 49:167-83. [PMID: 22218826 DOI: 10.1007/s00592-011-0364-z] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/23/2011] [Accepted: 12/19/2011] [Indexed: 12/27/2022]
Abstract
In the present article, we propose the perspective that abnormal glutamate homeostasis might contribute to diabetes pathogenesis. Previous reports and our recent data indicate that chronically high extracellular glutamate levels exert direct and indirect effects that might participate in the progressive loss of β-cells occurring in both T1D and T2D. In addition, abnormal glutamate homeostasis may impact all the three accelerators of the "accelerator hypothesis" and could partially explain the rising frequency of T1D and T2D.
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Affiliation(s)
- Alberto M Davalli
- Diabetes and Endocrinology Unit, Department of Internal Medicine, San Raffaele Scientific Institute, 20132, Milan, Italy.
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Minor RK, López M, Younts CM, Jones B, Pearson KJ, Anson RM, Diéguez C, de Cabo R. The arcuate nucleus and neuropeptide Y contribute to the antitumorigenic effect of calorie restriction. Aging Cell 2011; 10:483-92. [PMID: 21385308 PMCID: PMC3094497 DOI: 10.1111/j.1474-9726.2011.00693.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Calorie restriction (CR) is known to have profound effects on tumor incidence. A typical consequence of CR is hunger, and we hypothesized that the neuroendocrine response to CR might in part mediate CR's antitumor effects. We tested CR under appetite suppression using two models: neuropeptide Y (NPY) knockout mice and monosodium glutamate-injected mice. While CR was protective in control mice challenged with a two-stage skin carcinogenesis model, papilloma development was neither delayed nor reduced by CR in the monosodium glutamate-treated and NPY knockout mice. Adiponectin levels were also not increased by CR in the appetite-suppressed mice. We propose that some of CR's beneficial effects cannot be separated from those imposed on appetite, and that NPY neurons in the arcuate nucleus of the hypothalamus are involved in the translation of reduced intake to downstream physiological and functional benefits.
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Affiliation(s)
- Robin K. Minor
- Laboratory of Experimental Gerontology, National Institute on Aging, National Institutes of Health, 251 Bayview Boulevard, Suite 100 Room 9C218, Baltimore, Maryland, 21224, USA
| | - Miguel López
- Department of Physiology, School of Medicine, University of Santiago de Compostela-Instituto de Investigación Sanitaria, S. Francisco s/n, Santiago de Compostela (A Coruña), 15782, Spain
- CIBER Fisiopatología de la Obesidad y Nutrición (CIBERobn), Spain
| | - Caitlin M. Younts
- Laboratory of Experimental Gerontology, National Institute on Aging, National Institutes of Health, 251 Bayview Boulevard, Suite 100 Room 9C218, Baltimore, Maryland, 21224, USA
| | - Bruce Jones
- Laboratory of Experimental Gerontology, National Institute on Aging, National Institutes of Health, 251 Bayview Boulevard, Suite 100 Room 9C218, Baltimore, Maryland, 21224, USA
| | - Kevin J. Pearson
- Laboratory of Experimental Gerontology, National Institute on Aging, National Institutes of Health, 251 Bayview Boulevard, Suite 100 Room 9C218, Baltimore, Maryland, 21224, USA
- Graduate Center for Nutritional Sciences, University of Kentucky, C.T. Wethington Bldg, Rm 591, Lexington, KY 40536, USA
| | - R. Michael Anson
- Laboratory of Experimental Gerontology, National Institute on Aging, National Institutes of Health, 251 Bayview Boulevard, Suite 100 Room 9C218, Baltimore, Maryland, 21224, USA
- CCBC School of Mathematics and Science, 7200 Sollers Point Road, Room E210B, Baltimore, MD, 21222
| | - Carlos Diéguez
- Department of Physiology, School of Medicine, University of Santiago de Compostela-Instituto de Investigación Sanitaria, S. Francisco s/n, Santiago de Compostela (A Coruña), 15782, Spain
- CIBER Fisiopatología de la Obesidad y Nutrición (CIBERobn), Spain
| | - Rafael de Cabo
- Laboratory of Experimental Gerontology, National Institute on Aging, National Institutes of Health, 251 Bayview Boulevard, Suite 100 Room 9C218, Baltimore, Maryland, 21224, USA
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Leasure JL, Giddabasappa A, Chaney S, Johnson JE, Pothakos K, Lau YS, Fox DA. Low-level human equivalent gestational lead exposure produces sex-specific motor and coordination abnormalities and late-onset obesity in year-old mice. ENVIRONMENTAL HEALTH PERSPECTIVES 2008; 116:355-61. [PMID: 18335103 PMCID: PMC2265051 DOI: 10.1289/ehp.10862] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2007] [Accepted: 12/07/2007] [Indexed: 05/02/2023]
Abstract
BACKGROUND Low-level developmental lead exposure is linked to cognitive and neurological disorders in children. However, the long-term effects of gestational lead exposure (GLE) have received little attention. OBJECTIVES Our goals were to establish a murine model of human equivalent GLE and to determine dose-response effects on body weight, motor functions, and dopamine neurochemistry in year-old offspring. METHODS We exposed female C57BL/6 mice to water containing 0, 27 (low), 55 (moderate), or 109 ppm (high) of lead from 2 weeks prior to mating, throughout gestation, and until postnatal day 10 (PN10). Maternal and litter measures, blood lead concentrations ([BPb]), and body weights were obtained throughout the experiment. Locomotor behavior in the absence and presence of amphetamine, running wheel activity, rotarod test, and dopamine utilization were examined in year-old mice. RESULTS Peak [BPb] were < 1, < or = 10, 24-27, and 33-42 microg/dL in control, low-, moderate- and high-dose GLE groups at PN0-10, respectively. Year-old male but not female GLE mice exhibited late-onset obesity. Similarly, we observed male-specific decreased spontaneous motor activity, increased amphetamine-induced motor activity, and decreased rotarod performance in year-old GLE mice. Levels of dopamine and its major metabolite were altered in year-old male mice, although only forebrain utilization increased. GLE-induced alterations were consistently larger in low-dose GLE mice. CONCLUSIONS Our novel results show that GLE produced permanent male-specific deficits. The nonmonotonic dose-dependent responses showed that low-level GLE produced the most adverse effects. These data reinforce the idea that lifetime measures of dose-response toxicant exposure should be a component of the neurotoxic risk assessment process.
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Affiliation(s)
- J. Leigh Leasure
- Department of Psychology
- Department of Biology and Biochemistry and
| | - Anand Giddabasappa
- Department of Biology and Biochemistry and
- College of Optometry, University of Houston, Houston, Texas, USA
| | - Shawntay Chaney
- Department of Biology and Biochemistry and
- College of Optometry, University of Houston, Houston, Texas, USA
| | - Jerry E. Johnson
- College of Optometry, University of Houston, Houston, Texas, USA
- Department of Natural Sciences, University of Houston-Downtown, Houston, Texas, USA
| | - Konstantinos Pothakos
- Department of Pharmacological and Pharmaceutical Sciences, University of Houston, Houston, Texas, USA
| | - Yuen Sum Lau
- Department of Pharmacological and Pharmaceutical Sciences, University of Houston, Houston, Texas, USA
| | - Donald A. Fox
- Department of Biology and Biochemistry and
- College of Optometry, University of Houston, Houston, Texas, USA
- Department of Pharmacological and Pharmaceutical Sciences, University of Houston, Houston, Texas, USA
- Address correspondence to D.A. Fox, University of Houston, College of Optometry, 4901 Calhoun Rd., Houston, TX 77204-2020 USA. Telephone: (713) 743-1964. Fax: (713) 743-2053. E-mail:
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Bartolomucci A, Possenti R, Levi A, Pavone F, Moles A. The role of the vgf gene and VGF-derived peptides in nutrition and metabolism. GENES & NUTRITION 2007; 2:169-80. [PMID: 18850173 PMCID: PMC2474945 DOI: 10.1007/s12263-007-0047-0] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2006] [Accepted: 10/24/2006] [Indexed: 12/01/2022]
Abstract
Energy homeostasis is a complex physiological function coordinated at multiple levels. The issue of genetic regulation of nutrition and metabolism is attracting increasing interest and new energy homeostasis-regulatory genes are continuously identified. Among these genes, vgf is gaining increasing interest following two observations: (1) VGF-/- mice have a lean and hypermetabolic phenotype; (2) the first VGF-derived peptide involved in energy homeostasis, named TLQP-21, has been identified. The aim of this review will be to discuss the role of the vgf gene and VGF derived peptides in metabolic and nutritional functions. In particular we will: (1) provide a brief overview on the central systems regulating energy homeostasis and nutrition particularly focusing on the melanocortin system; (2) introduce the structure and molecular characteristic of vgf; (3) describe the phenotype of VGF deficient mice; (4) present recent data on the metabolic role of VGF-derived peptides, particularly focusing on one peptide named TLQP-21.
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Affiliation(s)
- Alessandro Bartolomucci
- Institute of Neuroscience, CNR, Via del Fosso di Fiorano 64, 00143 Rome, Italy
- Dipartimento di Biologia Evolutiva e Funzionale, Università di Parma, V.le G.P. Usberti 11A, 43100 Parma, Italy
| | - Roberta Possenti
- Department of Neuroscience, University of Roma II-Tor Vergata, Rome, Italy
- Institute of Neurobiology and Molecular Medicine, CNR, Rome, Italy
| | - Andrea Levi
- Institute of Neurobiology and Molecular Medicine, CNR, Rome, Italy
| | - Flaminia Pavone
- Institute of Neuroscience, CNR, Via del Fosso di Fiorano 64, 00143 Rome, Italy
| | - Anna Moles
- Institute of Neuroscience, CNR, Via del Fosso di Fiorano 64, 00143 Rome, Italy
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10
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Kiss P, Hauser D, Tamás A, Lubics A, Rácz B, Horvath ZS, Farkas J, Zimmermann F, Stepien A, Lengvari I, Reglódi D. Changes in open-field activity and novelty-seeking behavior in periadolescent rats neonatally treated with monosodium glutamate. Neurotox Res 2007; 12:85-93. [PMID: 17967732 DOI: 10.1007/bf03033917] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Monosodium glutamate (MSG) treatment of neonatal rodents leads to degeneration of the neurons in the arcuate nucleus, inner retinal layers and various other brain areas. It also causes various changes in the motor activity, sensory performance and learning abilities. We have previously shown that MSG treatment delays the appearance of some reflexes during neurobehavioral development and leads to temporary changes in reflex performance and motor coordination. Investigation of novelty-seeking behavior is of growing importance for its relationship with sensitivity to psychomotor stimulants. Perinatal administration of numerous toxic agents has been shown to influence novelty-seeking behavior in rats, but little is known about the influence of neonatal MSG treatment on the novelty-seeking behavior. The aim of the present study was to compare changes in locomotor, spontaneous exploratory and novelty-seeking behavior in periadolescent rats neonatally treated with MSG. Newborn rats were treated with 4 mg/g MSG subcutaneously on postnatal days 1, 3, 5, 7 and 9. Open-field behavior was tested at 2, 3, 4, 6 and 8 weeks of age. We found that MSG administration led to only temporary increases in locomotor behavior, which was more pronounced during the first few postnatal weeks, followed by a subtle hypoactivity at 2 months of age. Novelty-seeking was tested in four 5-min trials at 3 weeks of age. Trial 1 was in an empty open-field, two identical objects were placed in the arena during trial 2 and 3, and one of them was replaced to a novel object during trial 4. We found that the behavioral pattern of MSG-treated rats was the opposite in all tested signs in the novelty exploration test compared to control pups. In summary, our present study shows that neonatal MSG treatment leads to early temporary changes in the locomotor activity followed by hypoactivity at 2 months of age. Furthermore, MSG-treated rats show a markedly disturbed novelty-seeking behavior represented by altered activity when subjected to a novel object.
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Affiliation(s)
- P Kiss
- Department of Anatomy, University of Pecs, Medical Faculty, Hungary
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11
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Kiss P, Tamas A, Lubics A, Szalai M, Szalontay L, Lengvari I, Reglodi D. Development of neurological reflexes and motor coordination in rats neonatally treated with monosodium glutamate. Neurotox Res 2005; 8:235-44. [PMID: 16371318 DOI: 10.1007/bf03033977] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Monosodium glutamate (MSG) treatment of neonatal rats causes neuronal degeneration in various brain areas and leads to several neurochemical, endocrinological and behavioral alterations. However, relatively little is known about the development of neurological reflexes and motor coordination of these animals. Therefore, the aim of the present study was to examine the neurobehavioral development of newborn rats treated with MSG. Rats received MSG at postnatal days 1, 3, 5, 7, and 9. Appearance of neural reflexes and reflex performance as well as motor coordination were examined for 5 weeks after birth. The efficacy of MSG treatment was confirmed by histological examination of the arcuate nucleus. We found that MSG treatment delayed the appearance of forelimb placing, forelimb grasp and righting reflexes, besides the retarded somatic development. The treated pups performed surface righting in significantly longer times. Also, worse performance was observed in the foot-fault and rota-rod tests. However, MSG-treated rats reached control levels by the end of the fifth postnatal week. These results show that MSG treatment does not cause permanent alterations in the neurobehavioral development, only delays the appearance of some reflexes and leads to temporary changes in reflex performance and motor coordination signs.
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Affiliation(s)
- P Kiss
- Department of Anatomy, Neurohumoral Regulations Research Group of the Hungarian Academy of Sciences, University of Pecs, Hungary
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12
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Metzger D, Imai T, Jiang M, Takukawa R, Desvergne B, Wahli W, Chambon P. Functional role of RXRs and PPARgamma in mature adipocytes. Prostaglandins Leukot Essent Fatty Acids 2005; 73:51-8. [PMID: 15936932 DOI: 10.1016/j.plefa.2005.04.007] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
The peroxisome proliferator-activated receptor gamma (PPARgamma) is abundantly expressed in adipocytes, and plays an important role in adipocyte differentiation and fat accretion. It is a heterodimeric partner of the retinoid X receptors alpha, beta and gamma, which are also expressed in the adipose tissue. As lethality of PPARgamma(-/-) and RXRalpha(-/-) mouse fetuses precluded the analysis of PPARgamma and RXRalpha functions in mature adipocytes, we generated RXRalpha(ad-/-) and PPARgamma(ad-/-) mice, in which RXRalpha and PPARgamma are selectively ablated in adult adipocytes, respectively. Even though the adiposity of RXRalpha(ad-/-) mice is similar to that of control mice when fed a regular diet, they are resistant to chemically and dietary-induced obesity. However, mature adipocytes lacking either both RXRalpha and RXRgamma or PPARgamma die, and are replaced by newly formed adipocytes. Thus, in adipocytes, RXRalpha is essential for lipogenesis, but RXRgamma can functionally replace RXRalpha for the adipocyte vital functions exerted by PPARgamma/RXR heterodimers.
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Affiliation(s)
- D Metzger
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC) INSERM/CNRS/ULP, 1, rue Laurent Fries, 67404 ILLKIRCH, France.
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Diniz YS, Fernandes AAH, Campos KE, Mani F, Ribas BO, Novelli ELB. Toxicity of hypercaloric diet and monosodium glutamate: oxidative stress and metabolic shifting in hepatic tissue. Food Chem Toxicol 2004; 42:313-19. [PMID: 14667476 DOI: 10.1016/j.fct.2003.09.006] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The present study examines the effects of a hypercaloric diet on hepatic glucose metabolism of young rats, with and without monosodium glutamate (MSG) administration, and the association of these treatments with evaluating markers of oxidative stress. Male weaned Wistar rats (21 days old) from mothers fed with a hypercaloric diet or a normal diet, were divided into four groups (n=6): control (C) fed with control diet; (MSG) treated with MSG (4 mg/g) and control diet; (HD) fed with hypercaloric diet and (MSG-HD) treated with MSG and HD. Rats were sacrificed after the oral glucose tolerance test (OGTT), at 45 days of treatments. Serum was used for insulin determination. Glycogen, hexokinase(HK), glucose-6-phosphatase(G6PH), lipid hydroperoxide, superoxide dismutase(SOD) and glutathione peroxidase(GSH-Px) were determined in liver. HD rats showed hypoglycemia, hyperinsulinemia, and high hepatic glycogen, HK and decreased G6PH. MSG and MSG-HD had hyperinsulinemia, hyperglycemia, decreased HK and increased G6PH in hepatic tissue. These animals had impaired OGTT. HD, MSG and MSG-HD groups had increased lipid hydroperoxide and decreased SOD in hepatic tissue. Hypercaloric diet and monosodium glutamate administration induced alterations in metabolic rate of glucose utilization and decreased antioxidant defenses. Therefore, the hepatic glucose metabolic shifting induced by HD intake and MSG administration were associated with oxidative stress in hepatic tissue.
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Affiliation(s)
- Yeda S Diniz
- Post Graduation Course Department of Clinical and Cardiology, Faculty of Medicine, UNESP, Botucatu, São Paulo, Brazil
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Singh P, Mann KA, Mangat HK, Kaur G. Prolonged glutamate excitotoxicity: effects on mitochondrial antioxidants and antioxidant enzymes. Mol Cell Biochem 2003; 243:139-45. [PMID: 12619899 DOI: 10.1023/a:1021668314070] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Glutamate, a major excitatory amino acid neurotransmitter is also an endogenous excitotoxin. The present study examined the prolonged and delayed effects of glutamate excitotoxicity on mitochondrial lipid peroxidation and antioxidant parameters in different brain regions, namely, cerebral hemisphere, cerebellum, brain stem and diencephalon. Wistar rats (male) were exposed to monosodium glutamate (MSG) (4 mg x g body wt(-1), i.p.) for 6 consecutive days and sacrificed on 30th and 45th day after last MSG dose. MSG treatment markedly decreased the mitochondrial manganese superoxide-dismutase (Mn-SOD), catalase and reduced glutathione (GSH) content, and increased the lipid peroxidation (LPx), uric acid and glutathione peroxidase (GPx) activity. These results indicate that oxidative stress produced by glutamate in vulnerable brain regions may persist for longer periods and mitochondrial function impairment is an important mechanism of excitatory amino acid mediated neurotoxicity in chronic neurodegeneration.
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Affiliation(s)
- Puneet Singh
- Neurochemistry and Neuroendocrinology Laboratory, Department of Biotechnology, Guru Nanak Dev University, Amritsar, India
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15
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VGF is required for obesity induced by diet, gold thioglucose treatment, and agouti and is differentially regulated in pro-opiomelanocortin- and neuropeptide Y-containing arcuate neurons in response to fasting. J Neurosci 2002. [PMID: 12177191 DOI: 10.1523/jneurosci.22-16-06929.2002] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Targeted deletion of the gene encoding the neuronal and neuroendocrine secreted polypeptide VGF (nonacronymic) produces a lean, hypermetabolic mouse. Consistent with this phenotype, VGF mRNA levels are regulated in the hypothalamic arcuate nucleus in response to fasting. To gain insight into the site(s) and mechanism(s) of action of VGF, we further characterized VGF expression in the hypothalamus. Double-label studies indicated that VGF and pro-opiomelanocortin were coexpressed in lateral arcuate neurons in the fed state, and that VGF expression was induced after fasting in medial arcuate neurons that synthesize neuropeptide Y (NPY). Like NPY, VGF mRNA induction in this region of the hypothalamus in fasted mice was inhibited by exogenous leptin. In leptin-deficient ob/ob and receptor-mutant db/db mice, VGF mRNA levels in the medial arcuate were elevated. To identify neural pathways that are functionally compromised by Vgf ablation, VGF mutant mice were crossed with obese A(y)/a (agouti) and ob/ob mice. VGF deficiency completely blocked the development of obesity in A(y)/a mice, whereas deletion of Vgf in ob/ob mice attenuated weight gain but had no impact on adiposity. Hypothalamic levels of NPY and agouti-related polypeptide mRNAs in both double-mutant lines were dramatically elevated 10- to 15-fold above those of wild-type mice. VGF-deficient mice were also found to resist diet- and gold thioglucose-induced obesity. These data and the susceptibility of VGF mutant mice to monosodium glutamate-induced obesity are consistent with a role for VGF in outflow pathways, downstream of hypothalamic and/or brainstem melanocortin 4 receptors, that project via the autonomic nervous system to peripheral metabolic tissues and regulate energy homeostasis.
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16
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Abstract
Weight control is dependent on energy balance. Reduced energy expenditure (EE) associated with decreased physical activity is suggested to be a major underlying cause in the increasing prevalence of weight gain and obesity. Therefore, a better understanding of the biological determinants involved in the regulation of physical activity is essential. To facilitate interpretation in humans, it is helpful to consider the evidence from animal studies. This review focuses on animal studies examining the biological determinants influencing activity and potential implications to human. It appears that physical activity is influenced by a number of parameters. However, regardless of the parameter involved, body weight appears to play an underlying role in the regulation of activity. Furthermore, the regulation of activity associated with body weight appears to occur only after the animal achieves a critical weight. This suggests that activity levels are a consequence rather than a contributor to weight control. However, the existence of an inverse weight-activity relationship remains inconclusive. Confounding the results are the multifactorial nature of physical activity and the lack of appropriate measuring devices. Furthermore, many determinants of body weight are closely interlocked, making it difficult to determine whether a single, combination, or interaction of factors is important for the regulation of activity. For example, diet-induced obesity, aging, lesions to the ventral medial hypothalamus, and genetics all produce hypoactivity. Providing a better understanding of the biological determinants involved in the regulation of activity has important implications for the development of strategies for the prevention of weight gain leading to obesity and subsequent morbidity and mortality in the human population.
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Affiliation(s)
- Janet C L Tou
- Lockheed Martin Engineering and Sciences, and National Aeronautics and Space Administration (NASA) Ames Research Center, Life Sciences Division, NASA Ames Research Center, Moffett Field, California 94035, USA
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Impaired adipogenesis and lipolysis in the mouse upon selective ablation of the retinoid X receptor alpha mediated by a tamoxifen-inducible chimeric Cre recombinase (Cre-ERT2) in adipocytes. Proc Natl Acad Sci U S A 2001; 98. [PMID: 11134524 PMCID: PMC14572 DOI: 10.1073/pnas.011528898] [Citation(s) in RCA: 97] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Retinoid X receptor alpha (RXRalpha) is involved in multiple signaling pathways, as a heterodimeric partner of several nuclear receptors. To investigate its function in energy homeostasis, we have selectively ablated the RXRalpha gene in adipocytes of 4-week-old transgenic mice by using the tamoxifen-inducible Cre-ERT2 recombination system. Mice lacking RXRalpha in adipocytes were resistant to dietary and chemically induced obesity and impaired in fasting-induced lipolysis. Our results also indicate that RXRalpha is involved in adipocyte differentiation. Thus, our data demonstrate the feasibility of adipocyte-selective temporally controlled gene engineering and reveal a central role of RXRalpha in adipogenesis, probably as a heterodimeric partner for peroxisome proliferator-activated receptor gamma.
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Imai T, Jiang M, Chambon P, Metzger D. Impaired adipogenesis and lipolysis in the mouse upon selective ablation of the retinoid X receptor mediated by a tamoxifen-inducible chimeric Cre recombinase (Cre-ERT2) in adipocytes. Proc Natl Acad Sci U S A 2001; 98:224-8. [PMID: 11134524 PMCID: PMC14572 DOI: 10.1073/pnas.98.1.224] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Retinoid X receptor alpha (RXRalpha) is involved in multiple signaling pathways, as a heterodimeric partner of several nuclear receptors. To investigate its function in energy homeostasis, we have selectively ablated the RXRalpha gene in adipocytes of 4-week-old transgenic mice by using the tamoxifen-inducible Cre-ERT2 recombination system. Mice lacking RXRalpha in adipocytes were resistant to dietary and chemically induced obesity and impaired in fasting-induced lipolysis. Our results also indicate that RXRalpha is involved in adipocyte differentiation. Thus, our data demonstrate the feasibility of adipocyte-selective temporally controlled gene engineering and reveal a central role of RXRalpha in adipogenesis, probably as a heterodimeric partner for peroxisome proliferator-activated receptor gamma.
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Affiliation(s)
- T Imai
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, Centre National de la Recherche Scientifique/Institut National de la Santé et de la Recherche Médicale/Université Louis Pasteur, Collège de France, BP 163, 67404 Illkirch Cedex, France
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19
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Ali MM, Bawari M, Misra UK, Babu GN. Locomotor and learning deficits in adult rats exposed to monosodium-L-glutamate during early life. Neurosci Lett 2000; 284:57-60. [PMID: 10771161 DOI: 10.1016/s0304-3940(00)00958-7] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Neonatal administration of neurotoxic doses of monosodium-L-glutamate (MSG) to rats causes neuronal necrosis of the hypothalamus along with behavioral abnormalities. In the present study the behavioral effects in rats treated with subneurotoxic doses of MSG (2 mg/g, p.o., for 10 days) at the weaned stage were investigated at day 90 post-dosing. The MSG-treated rats did not show significant changes in any of the components of spontaneous locomotor activity but, after apomorphine challenge, marked decreases in the distance travelled, ambulatory and stereotypic times, and the number of stereotypic movements with an increase in the resting time were observed. Significant decrease in the active avoidance learning performance was observed in the MSG-treated rats in the learning (acquisition) phase without any changes in the extinction and relearning phases. The results indicate that exposure to MSG in early life in rats could lead to subtle behavioral aberrations in late adulthood.
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Affiliation(s)
- M M Ali
- Neurotoxicology Section, Industrial Toxicology Research Centre, P.O. Box 80, M.G. Marg, Lucknow, India
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20
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Caputo FA, Ali SF, Wolff GL, Scallet AC. Neonatal MSG reduces hypothalamic DA, beta-endorphin, and delays weight gain in genetically obese (A viable yellow/alpha) mice. Pharmacol Biochem Behav 1996; 53:425-32. [PMID: 8808153 DOI: 10.1016/0091-3057(95)02009-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Neonatal treatment with monosodium glutamate (MSG) decreases proopiomelanocortin (POMC) peptides and results in obesity. The yellow mouse is a model of obesity induced by the viable yellow (Avy) gene at the agouti locus on Chromosome 2, which results in overproduction of a POMC receptor antagonist. Thus we hypothesized that MSG, when imposed on the genetically susceptible model, would alter the development of obesity. Both yellow obese (Avy) and black lean (alpha/alpha) males were injected on Postnatal Days 1, 3, 5, 7, and 9 with 2.0 mg/g body weight MSG or saline SC. Their food intake, growth parameters, and neurochemical status were examined. Paradoxically, MSG interacted with the yellow phenotype to delay the rapid rate of weight gain characteristic of this model (p < 0.05). Food intake was decreased (p < 0.05) in both phenotypes treated with MSG, as was hypothalamic content of dopamine (p < 0.05) and of the POMC peptide, beta-endorphin (p < 0.001). The yellow obese phenotype was more sensitive than the black lean phenotype to the neurochemical effect of early postnatal MSG administration. Recent reports suggest the agouti locus protein is an antagonist of the receptor for another POMC peptide, melanocyte-stimulating hormone (MSH). Therefore, the balance of functional activity between various POMC peptides appears to be an important factor in the development of both acquired and genetic obesity.
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Affiliation(s)
- F A Caputo
- Division of Neurotoxicology, National Center for Toxicological Research/USFDA, Jefferson, AR 72079, USA
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21
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Ohmori H, Kobayashi T, Yasuda M. Neurotoxicity of phenytoin administered to newborn mice on developing cerebellum. Neurotoxicol Teratol 1992; 14:159-65. [PMID: 1635536 DOI: 10.1016/0892-0362(92)90011-x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
To examine the neurotoxic effects of phenytoin (PHT) on cerebellar development, we administered 50 mg/kg PHT suspended in sesame oil orally to newborn Jcl:ICR mice once a day during postnatal days 2-14 and determined plasma PHT concentrations at designated intervals during the administration period. In the treated group, walking reflex and negative geotaxis were poorly developed on postnatal day 14. Pyknotic cells in the external granular layer (EGL) significantly increased and were prominent in the vermis area compared with controls on postnatal day 14. Plasma PHT levels were 34-36 micrograms/ml on the 3rd day of PHT treatment and approached a steady-state situation. Total brain weight, size of the cerebellum, and cerebellar weight were significantly reduced in the treated group on postnatal day 56. Accordingly, oral administration of PHT in the neonatal period induced neurotoxic damage on the developing cerebellum.
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Affiliation(s)
- H Ohmori
- Department of Anatomy, Hiroshima University School of Medicine, Japan
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22
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Rodier PM, Kates B, White WA, White AL. The relationship of rat brain weight and pituitary weight to postnatal growth after prenatal exposure to methylazoxymethanol. Neurotoxicol Teratol 1991; 13:583-90. [PMID: 1779946 DOI: 10.1016/0892-0362(91)90041-t] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Teratogens can affect body weight in various ways, but the association of brain damage with postnatal growth abnormalities suggests a role for neuroendocrine growth-controlling systems. Growth deficiencies follow methylazoxymethanol (MAM) exposure during the period when the growth hormone releasing factor (GRF) cells of the hypothalamus form, and the pattern of growth of the animals is like that of animals deficient in growth hormone. The present studies were designed to examine the growth, body proportions, brain weight, and pituitary weight of animals treated with 20 mg/kg MAM on the 13th day of gestation, a peak period for production of GRF neurons. Among the offspring, this treatment produced about 25% dwarfs (animals smaller than the smallest control of the same sex). Significantly more females than males were categorized as dwarfs. The weight effect occurred long after birth, as is characteristic of animals and humans with growth hormone deficiency. Analyses of weights over the course of development indicated that prenatal factors, rather than factors operating between birth and weaning, predicted the adult body weight of dwarfs, while both sets of factors were significant in other animals. The growth reduction was symmetrical, as would be expected if the animals were growth hormone deficient, with an 18% reduction in weight reflecting a 6% reduction in bone length. The remaining treated animals were similar to controls in absolute weight, body proportions, and rate of growth. Neither pituitary weight nor brain weight appears to play the key role in determining which animals will exhibit growth deficiency.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- P M Rodier
- Department of Obstetrics and Gynecology, University of Rochester School of Medicine and Dentistry, NY 14642
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23
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Fisher KN, Turner RA, Pineault G, Kleim J, Saari MJ. The postweaning housing environment determines expression of learning deficit associated with neonatal monosodium glutamate (M.S.G.). Neurotoxicol Teratol 1991; 13:507-13. [PMID: 1758404 DOI: 10.1016/0892-0362(91)90058-5] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Perinatal M.S.G. treatment causes a syndrome characterized by damage to the hypothalamic arcuate nucleus, other circumventricular areas, parts of the visual system and the dentate gyrus of the hippocampus. The resulting hormonal dysfunction may be responsible for developmental anomalies of organ systems, obesity, and alterations in sensory/motor performance. We have shown that some behavioral indicators of M.S.G. toxicity in rats can be masked by rearing them in enriched housing conditions. Here, we evaluated the impact of six housing conditions on M.S.G.-induced alterations of organ systems and behavior. Perinatal M.S.G. treatment reduced adrenal, heart and testes weights, as well as total white blood cell (WBC) counts, and increased tail flick latencies. These measures were unaffected by the housing condition. M.S.G.-induced reductions in body weight, grip strength, water maze and dominance task performance varied as a function of housing. Deficits in water maze performance were most evident following social and isolated single-cage housing. We propose that deficits in water maze performance following perinatal M.S.G. may be attributable to hippocampal damage that can be alleviated by rearing the rats in stimulating environments.
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Affiliation(s)
- K N Fisher
- Neuroscience Research Unit, Nipissing University College, North Bay, Ontario, Canada
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25
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Liu WK, Wong CC, Mak NK. Effects of neonatal monosodium-L-glutamate treatment on rat alveolar macrophages. Chem Biol Interact 1989; 69:193-201. [PMID: 2495191 DOI: 10.1016/0009-2797(89)90077-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Treatment of neonatal rats with repeated doses of monosodium-L-glutamate resulted in changes of morphology and function of alveolar macrophages recovered from adult female rats. Numerous cellular lipid vacuoles and lamellar structures were observed in these alveolar macrophages under transmission electron microscopy. There was approximately 50% increase of cellular total lipid content measured by Oil-Red-O staining and colorimetric method. The yeast phagocytosis and intracellular killing ability, as well as the inhibitory effect on the growth of tumor cells were reduced in alveolar macrophages from neonatal MSG-treated rats.
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Affiliation(s)
- W K Liu
- Department of Anatomy, Chinese University of Hong Kong, Shatin
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26
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Dawson R, Bierkamper G. Flurothyl seizure thresholds in mice treated neonatally with a single injection of monosodium glutamate (MSG): evaluation of experimental parameters in flurothyl seizure testing. Pharmacol Biochem Behav 1987; 28:165-9. [PMID: 3685052 DOI: 10.1016/0091-3057(87)90208-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Monosodium glutamate (MSG) administration to neonatal rodents produces convulsions and results in numerous biochemical and behavioral deficits. These studies were undertaken to determine if neonatal administration of MSG produced permanent alterations in seizure susceptibility, since previous investigations were inconclusive. A flurothyl ether seizure screening technique was used to evaluate seizure susceptibility in adult mice that received neonatal injections of MSG (4 mg/g and 1 mg/g). MSG treatment resulted in significant reductions in whole brain weight but did not alter seizure threshold. A naloxone (5 mg/kg) challenge was also ineffective in altering the seizure thresholds of either control of MSG-treated mice. Flurothyl ether produced hypothermia which was correlated with the duration of flurothyl exposure; however, the relationship of hypothermia to seizure induction was unclear. Flurothyl seizure testing proved to be a rapid and reliable technique with which to evaluate seizure susceptibility.
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Affiliation(s)
- R Dawson
- Department of Pharmacodynamics, University of Florida, College of Pharmacy, J. Hillis Miller Health Center, Gainesville 32610
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Flier JS, Cook KS, Usher P, Spiegelman BM. Severely impaired adipsin expression in genetic and acquired obesity. Science 1987; 237:405-8. [PMID: 3299706 DOI: 10.1126/science.3299706] [Citation(s) in RCA: 204] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Adipsin, a serine protease homolog, is synthesized and secreted by adipose cells and is found in the bloodstream. The expression of adipsin messenger RNA (mRNA) and protein was analyzed in rodents during metabolic perturbations and in several experimental models of obesity. Adipsin mRNA abundance is increased in adipose tissue during fasting in normal rats and in diabetes due to streptozotocin-induced insulin deficiency. Adipsin mRNA abundance decreased during the continuous infusion of glucose, which induces a hyperglycemic, hyperinsulinemic state that is accompanied by an increased adipose mass; it is suppressed (greater than 100-fold) in two strains of genetically obese mice (db/db and ob/ob), compared to their congenic counterparts, and is also reduced when obesity is induced chemically by injection of monosodium glutamate into newborn mice. Circulating adipsin protein is decreased in these animal models of obesity, as determined by immunoblotting with antisera to adipsin. Little change in adipsin expression is observed in a model of obesity obtained by pure overfeeding of normal rats (cafeteria model). These data suggest a possible role for adipsin in the above-mentioned disordered metabolic states, and raise the possibility that adipsin expression may be used to distinguish obesities that arise from certain genetic or metabolic defects from those that result from pure overfeeding.
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Tokuyama K, Himms-Hagen J. Brown adipose tissue thermogenesis, torpor, and obesity of glutamate-treated mice. THE AMERICAN JOURNAL OF PHYSIOLOGY 1986; 251:E407-15. [PMID: 2876642 DOI: 10.1152/ajpendo.1986.251.4.e407] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Mice treated with glutamate in the neonatal period are known to develop into stunted obese adults, despite hypophagia. Our objective was to find out whether brown adipose tissue (BAT) thermogenic function might be abnormal in the glutamate-obese mouse. At 10 wk of age, group-housed glutamate-obese mice exhibited nocturnal and early diurnal torpor, i.e., they thermoregulated at a lower than normal body temperature. When exposed to 4 degrees C, they died in hypothermia within 24 h. They could adapt to living at 14 degrees C for up to 1 wk but failed to adjust their food intake sufficiently to maintain their body weight. Their fat stores were, nevertheless, conserved. BAT was present in increased amounts in glutamate-obese mice. Its thermogenic activity (as assessed by the level of mitochondrial GDP binding) was normal (male mice) or reduced (female mice). A normal thermogenic responsiveness of BAT to cold occurred. The thermogenic response of BAT to a cafeteria diet was normal (male mice) or reduced (female mice). Serum corticosterone concentration was increased in both male and female glutamate-treated mice particularly in the cold. We conclude that the high metabolic efficiency and obesity of the glutamate-obese mouse are principally a consequence of its maintenance of a hypothermic torpid state for more than 50% of the time. An additional deficit in energy expenditure in female, but not male, glutamate-obese mice is associated with suppressed responsiveness of the thermogenic function of BAT to diet and may account for the greater degree of obesity in female than in male glutamate-treated mice.
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Katz RJ. Neonatal monosodium glutamate differentially alters two models of behavioral activity in conjunction with reduced hypothalamic endorphins. Physiol Behav 1983; 31:147-51. [PMID: 6314404 DOI: 10.1016/0031-9384(83)90111-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Neurotoxic doses of monosodium glutamate were administered to neonatal male and female Sprague-Dawley rats for five days postpartum. The rats were tested at 6 months for alterations in two forms of activity--initial activity in an open field and overnight activity in a familiar cage. In comparison with age-, sex- and handling-matched littermate controls, experimental subjects exhibited increased open field behaviors and reduced overnight activity. Subsequent histology indicated marked reductions in arcuate and periarcuate cells which included but probably were not limited to beta-endorphin containing neurons. These findings indicate that neonatal MSG has long-term behavioral and neurological consequences, that some changes occur within behaviorally discrete systems, and that they may be associated with functional alterations within endogenous opioid systems, inter alia.
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Abstract
This review provides extensive presentation and evaluation of data relative to flavor potentiation, including the historical, chemical, organoleptic, metabolic, physiological, and consumptive properties of the commonly available flavor potentiators, which are primarily monosodium glutamate and 5'-nucleotides. In addition, their food occurrences, mode of action, manufacturing procedures, and methods of analyses will be discussed. Also, attention will be given to miscellaneous compounds that possess flavor potentiating properties.
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Iwata S, Ichimura M, Matsuzawa Y, Takasaki Y, Sasaoka M. Behavioural studies in rats treated with monosodium l-glutamate during the early stages of life. Toxicol Lett 1979. [DOI: 10.1016/0378-4274(79)90045-6] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Studies on reproductive endocrine function in rats treated with monosodium l-glutamate early in life. Toxicol Lett 1979. [DOI: 10.1016/0378-4274(79)90046-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Vorhees CV, Butcher RE, Brunner RL, Sobotka TJ. A developmental test battery for neurobehavioral toxicity in rats: a preliminary analysis using monosodium glutamate calcium carrageenan, and hydroxyurea. Toxicol Appl Pharmacol 1979; 50:267-82. [PMID: 505457 DOI: 10.1016/0041-008x(79)90152-2] [Citation(s) in RCA: 110] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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Kanarek RB, Meyers J, Meade RG, Mayer J. Juvenile-onset obesity and deficits in caloric regulation in MSG-treated rats. Pharmacol Biochem Behav 1979; 10:717-21. [PMID: 493287 DOI: 10.1016/0091-3057(79)90324-1] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Caloric regulation and the development of obesity were examined in rats which had received parenteral injections of monosodium glutamate (MSG) as neonates. Rats were injected with either 2 mg/g or 4 mg/g MSG on alternate days for the first 20 days of life. Lee Indices of obesity were calculated at 22, 70, and 130 days of age. Animals in the 4 mg/g group were significantly more obese than controls at all three ages. However, both food intake and body weight of this group were significantly lower than those of controls. In adulthood, the ability to regulate caloric intake was tested by allowing animals access to diets of varying caloric densities. While control animals maintained relatively constant caloric intakes across dietary conditions, MSG-treated animals demonstrated an inability to respond to caloric challenges. Treated animals decreased caloric intake on a diluted diet and consumed more calories than controls when presented with a calorically dense diet. This inability to regulate caloric intake is compared with regulatory deficits observed in animals sustaining lesions of the ventromedial hypothalamus. The value of an animal model of juvenile-onset obesity is also discussed.
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Pizzi WJ, Tabor JM, Barnhart JE. Somatic, behavioral, and reproductive disturbances in mice following neonatal administration of sodium L-aspartate. Pharmacol Biochem Behav 1978; 9:481-5. [PMID: 733835 DOI: 10.1016/0091-3057(78)90046-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Sodium L-aspartate (ASP) was administered to neonatal mice according to an increasing dose schedule from Days 2--11 after birth. Adult ASP-treated animals showed large increases in body weight over controls along with stunted body length. The ASP group also showed decreases in locomotor and exploratory behavior. Reproductive dysfunction occurred in both female and male ASP-treated animals. Among treated animals, females had fewer pregnancies and smaller litters while males showed reduced fertility. Evidence of multiple endocrine dysfunction in ASP-treated animals was reflected by decreased pituitary, thyroid, ovaries and tested weights, along with delayed onset of puberty in females. These results demonstrate that sodium L-aspartate produces a syndrome similar to that seen following the administration of monosodium L-glutamate.
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Pizzi WJ, Barnhart JE, Fanslow DJ. Monosodium glutamate admlinistration to the newborn reduces reproductive ability in female and male mice. Science 1977; 196:452-4. [PMID: 557837 DOI: 10.1126/science.557837] [Citation(s) in RCA: 39] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Monosodium glutamate (MSG) administered during the neonatal period (days 2 to 11) resulted in a sequence of events that were manifested in adulthood. Reproductive dysfunction was seen in both female and male animals. Females treated with MSG had fewer pregnancies and smaller litters, while males treated with MSG showed reduced fertility. The MSG-treated mice showed increased body weight and decreased pituitary, thyroid, ovary, or testis weights.
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