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Abstract
Oxytocin and oxytocin receptors are synthesized in the periphery where paracrine/autocrine actions have been described alongside endocrine actions effected by central release of oxytocin from the posterior pituitary. In the female reproductive system, classical actions of uterine contraction and milk ejection from mammary glands are accompanied by actions in the ovaries where roles in steroidogenesis, follicle recruitment and ovulation have been described. Steroidogenesis, contractile activity, and gamete health are similarly affected by oxytocin in the male reproductive tract. In the cardiovascular system, a local oxytocinergic system appears to play an important cardio-protective role. This role is likely associated with emerging evidence that peripheral oxytocin is an important hormone in the endocrinology of glucose homeostasis due to its actions in adipose, the pancreas, and the largely ignored oxytocinergic systems of the adrenal glands and liver. Gene polymorphisms are shown to be associated with a number of reported traits, not least factors associated with metabolic syndrome.
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Affiliation(s)
- Stephen J Assinder
- Discipline of Physiology, School of Medical Sciences, Faculty of Medicine and Health, University of Sydney, Camperdown, NSW, Australia.
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Krskova K, Balazova L, Dobrocsyova V, Olszanecki R, Suski M, Chai SY, Zorad Š. Insulin-Regulated Aminopeptidase Inhibition Ameliorates Metabolism in Obese Zucker Rats. Front Mol Biosci 2020; 7:586225. [PMID: 33344504 PMCID: PMC7746680 DOI: 10.3389/fmolb.2020.586225] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Accepted: 11/06/2020] [Indexed: 12/14/2022] Open
Abstract
The aim of our study was to determine the influence of inhibition of insulin-regulated aminopeptidase/oxytocinase (IRAP) on glucose tolerance and metabolism of skeletal muscle and visceral adipose tissue in obese Zucker rats. Obese Zucker rats administered with IRAP inhibitor-HFI-419 at a dose of 29 μg/100 g BW/day by osmotic minipumps implanted subcutaneously for 2 weeks. Two-hour intraperitoneal glucose tolerance test (ipGTT) was performed in fasting rats. Plasma oxytocin levels were measured by enzyme immunoassay after plasma extraction. In the musculus quadriceps and epididymal adipose tissue, the expression of factors affecting tissue oxidative status and metabolism was determined by real-time qPCR and/or Western blot analysys. The plasma and tissue enzymatic activities were determined by colorimetric or fluorometric method. Circulated oxytocin levels in obese animals strongly tended to increase after HFI-419 administration. This was accompanied by significantly improved glucose utilization during ipGTT and decreased area under the curve (AUC) for glucose. In skeletal muscle IRAP inhibitor treatment up-regulated enzymes of antioxidant defense system - superoxide dismutase 1 and 2 and improved insulin signal transduction pathway. HFI-419 increased skeletal muscle aminopeptidase A expression and activity and normalized its plasma levels in obese animals. In epididymal adipose tissue, gene expression of markers of inflammation and adipocyte hypertrophy was down-regulated in obese rats after HFI-419 treatment. Our results demonstrate that IRAP inhibition improves whole-body glucose tolerance in insulin-resistant Zucker fatty rats and that this metabolic effect of HFI-419 involves ameliorated redox balance in skeletal muscle.
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Affiliation(s)
- Katarina Krskova
- Institute of Experimental Endocrinology, Biomedical Research Center, Department of Endocrine Regulations and Psychofarmacology, Slovak Academy of Sciences, Bratislava, Slovakia
| | - Lucia Balazova
- Institute of Experimental Endocrinology, Biomedical Research Center, Department of Endocrine Regulations and Psychofarmacology, Slovak Academy of Sciences, Bratislava, Slovakia
| | - Viktoria Dobrocsyova
- Institute of Experimental Endocrinology, Biomedical Research Center, Department of Endocrine Regulations and Psychofarmacology, Slovak Academy of Sciences, Bratislava, Slovakia
| | - Rafal Olszanecki
- Department of Pharmacology, Jagiellonian University Medical College, Cracow, Poland
| | - Maciej Suski
- Department of Pharmacology, Jagiellonian University Medical College, Cracow, Poland
| | - Siew Yeen Chai
- Monash Biomedicine Discovery Institute, Department of Physiology, Monash University, Clayton, VIC, Australia
| | - Štefan Zorad
- Institute of Experimental Endocrinology, Biomedical Research Center, Department of Endocrine Regulations and Psychofarmacology, Slovak Academy of Sciences, Bratislava, Slovakia
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Quines CB, Jardim NS, Araujo PCO, Cechella JL, Prado VC, Nogueira CW. Resistance training restores metabolic alterations induced by monosodium glutamate in a sex-dependent manner in male and female rats. J Cell Biochem 2019; 120:13426-13440. [PMID: 30916837 DOI: 10.1002/jcb.28617] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2018] [Revised: 01/14/2019] [Accepted: 01/28/2019] [Indexed: 01/07/2023]
Abstract
Despite resistance exercises being associated with health outcomes, numerous issues are still unresolved and further research is required before the exercise can faithfully be prescribed as medicine. The goal of this study was to investigate whether there are sex differences in resistance training effects on metabolic alterations induced by monosodium glutamate (MSG), a model of obesity, in male and female rats. Male and female Wistar rats received MSG (4 g/kg body weight/day, s.c.) from postnatal day 1 to 10. After 10 days from MSG administration, the rats were separated into two groups: MSG-sedentary and MSG-exercised. At postnatal day 60, the animals started a resistance training protocol in an 80 degrees inclined vertical ladder apparatus and performed it for 7 weeks. Control rats received saline solution and were divided in saline-sedentary and saline-exercised. Resistance training restored all plasma biochemical parameters (glucose, cholesterol, triglycerides, aspartate aminotransferase, and alanine aminotransferase) increased in male and female rats treated with MSG. The MSG administration induced hyperglycemia associated with a decrease in the skeletal muscle glucose transporter 4 (GLUT4) levels and accompanied by deregulation in proteins, G-6Pase, and tyrosine aminotransferase, involved in hepatic glucose metabolism of male and female rats. MSG induced dyslipidemia and lipotoxicity in the liver and skeletal muscle of male rats. Regarding female rats, lipotoxicity was found only in the skeletal muscle. The resistance training had beneficial effects against metabolic alterations induced by MSG in male and female rats, through regulation of proteins (GLUT2, protein kinase B, and GLUT4) involved in glucose and lipid pathways in the liver and skeletal muscle.
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Affiliation(s)
- Caroline B Quines
- Departamento de Bioquímica e Biologia Molecular, Laboratório de Síntese, Reatividade e Avaliação Farmacológica e Toxicológica de Organocalcogênios, Centro de Ciências Naturais e Exatas, Universidade Federal de Santa Maria, Santa Maria, Rio Grande do Sul, Brazil
| | - Natália S Jardim
- Departamento de Bioquímica e Biologia Molecular, Laboratório de Síntese, Reatividade e Avaliação Farmacológica e Toxicológica de Organocalcogênios, Centro de Ciências Naturais e Exatas, Universidade Federal de Santa Maria, Santa Maria, Rio Grande do Sul, Brazil
| | - Paulo Cesar O Araujo
- Departamento de Bioquímica e Biologia Molecular, Laboratório de Síntese, Reatividade e Avaliação Farmacológica e Toxicológica de Organocalcogênios, Centro de Ciências Naturais e Exatas, Universidade Federal de Santa Maria, Santa Maria, Rio Grande do Sul, Brazil
| | - José Luiz Cechella
- Departamento de Bioquímica e Biologia Molecular, Laboratório de Síntese, Reatividade e Avaliação Farmacológica e Toxicológica de Organocalcogênios, Centro de Ciências Naturais e Exatas, Universidade Federal de Santa Maria, Santa Maria, Rio Grande do Sul, Brazil
| | - Vinicius C Prado
- Departamento de Bioquímica e Biologia Molecular, Laboratório de Síntese, Reatividade e Avaliação Farmacológica e Toxicológica de Organocalcogênios, Centro de Ciências Naturais e Exatas, Universidade Federal de Santa Maria, Santa Maria, Rio Grande do Sul, Brazil
| | - Cristina W Nogueira
- Departamento de Bioquímica e Biologia Molecular, Laboratório de Síntese, Reatividade e Avaliação Farmacológica e Toxicológica de Organocalcogênios, Centro de Ciências Naturais e Exatas, Universidade Federal de Santa Maria, Santa Maria, Rio Grande do Sul, Brazil
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Alponti RF, Alves PL, Silveira PF. Novel adipocyte aminopeptidases are selectively upregulated by insulin in healthy and obese rats. J Endocrinol 2016; 228:97-104. [PMID: 26577934 DOI: 10.1530/joe-15-0266] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 11/17/2015] [Indexed: 12/17/2022]
Abstract
The lack of a complete assembly of the sensitivity of subcellular aminopeptidase (AP) activities to insulin in different pathophysiological conditions has hampered the complete view of the adipocyte metabolic pathways and its implications in these conditions. Here we investigated the influence of insulin on basic AP (APB), neutral puromycin-sensitive AP (PSA), and neutral puromycin-insensitive AP (APM) in high and low density microsomal and plasma membrane fractions from adipocytes of healthy and obese rats. Catalytic activities of these enzymes were fluorometrically monitoring in these fractions with or without insulin stimulus. Canonical traffic such as insulin-regulated AP was not detected for these novel adipocyte APs in healthy and obese rats. However, insulin increased APM in low density microsomal and plasma membrane fractions from healthy rats, APB in high density microsomal fraction from obese rats and PSA in plasma membrane fraction from healthy rats. A new concept of intracellular compartment-dependent upregulation of AP enzyme activities by insulin emerges from these data. This relatively selective regulation has pathophysiological significance, since these enzymes are well known to act as catalysts and receptor of peptides directly related to energy metabolism. Overall, the regulation of each one of these enzyme activities reflects certain dysfunction in obese individuals.
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Affiliation(s)
- Rafaela Fadoni Alponti
- Laboratory of PharmacologyUnit of Translational Endocrine Physiology and Pharmacology, Instituto Butantan, Avenida Vital Brasil, 1500, CEP05503-900 Sao Paulo, BrazilDepartment of PhysiologyUniversidade de Sao Paulo, Sao Paulo, Brazil Laboratory of PharmacologyUnit of Translational Endocrine Physiology and Pharmacology, Instituto Butantan, Avenida Vital Brasil, 1500, CEP05503-900 Sao Paulo, BrazilDepartment of PhysiologyUniversidade de Sao Paulo, Sao Paulo, Brazil
| | - Patricia Lucio Alves
- Laboratory of PharmacologyUnit of Translational Endocrine Physiology and Pharmacology, Instituto Butantan, Avenida Vital Brasil, 1500, CEP05503-900 Sao Paulo, BrazilDepartment of PhysiologyUniversidade de Sao Paulo, Sao Paulo, Brazil
| | - Paulo Flavio Silveira
- Laboratory of PharmacologyUnit of Translational Endocrine Physiology and Pharmacology, Instituto Butantan, Avenida Vital Brasil, 1500, CEP05503-900 Sao Paulo, BrazilDepartment of PhysiologyUniversidade de Sao Paulo, Sao Paulo, Brazil
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Alponti RF, Silveira PF. Adipocyte aminopeptidases in obesity and fasting. Mol Cell Endocrinol 2015; 415:24-31. [PMID: 26257241 DOI: 10.1016/j.mce.2015.07.032] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/22/2015] [Revised: 07/13/2015] [Accepted: 07/31/2015] [Indexed: 12/14/2022]
Abstract
This study checked the existence of a diverse array of aminopeptidase (AP) enzymes in high (HDM) and low (LDM) density microsomal and plasma membrane (MF) fractions from adipocytes of control, monosodium glutamate obese and food deprived rats. Gene expression was detected for ArgAP, AspAP, MetAP, and two AlaAP (APM and PSA). APM and PSA had the highest catalytic efficiency, whereas AspAP the highest affinity. Subcellular distribution of AP activities depended on metabolic status. Comparing catalytic levels, AspAP in HDM, LDM and MF was absent in obese and control under food deprivation; PSA in LDM was 3.5-times higher in obese than in normally fed control and control and obese under food deprivation; MetAP in MF was 4.5-times higher in obese than in food deprived obese. Data show new AP enzymes genetically expressed in subcellular compartments of adipocytes, three of them with altered catalytic levels that respond to whole-body energetic demands.
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Affiliation(s)
- Rafaela Fadoni Alponti
- Laboratory of Pharmacology, Instituto Butantan, Av. Vital Brasil, 1500, 05503-900, Sao Paulo, Brazil; Department of Physiology, Universidade de Sao Paulo, Rua do Matao, Travessa 14, 101, 05508-900, Sao Paulo, Brazil
| | - Paulo Flavio Silveira
- Laboratory of Pharmacology, Instituto Butantan, Av. Vital Brasil, 1500, 05503-900, Sao Paulo, Brazil.
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