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Zhao Y, Wang L, Liu S, Pu Y, Sun K, Xiao Y, Feng J. Adaptive Evolution of the Greater Horseshoe Bat AANAT: Insights into the Link between AANAT and Hibernation Rhythms. Animals (Basel) 2024; 14:1426. [PMID: 38791644 PMCID: PMC11117286 DOI: 10.3390/ani14101426] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2024] [Revised: 04/12/2024] [Accepted: 05/08/2024] [Indexed: 05/26/2024] Open
Abstract
Arylalkylamine N-acetyltransferase (AANAT) is a crucial rate-limiting enzyme in the synthesis of melatonin. AANAT has been confirmed to be independently duplicated and inactivated in different animal taxa in order to adapt to the environment. However, the evolutionary forces associated with having a single copy of AANAT remain unclear. The greater horseshoe bat has a single copy of AANAT but exhibits different hibernation rhythms in various populations. We analyzed the adaptive evolution at the gene and protein levels of AANAT from three distinct genetic lineages in China: northeast (NE), central east (CE), and southwest (SW). The results revealed greater genetic diversity in the AANAT loci of the NE and CE lineage populations that have longer hibernation times, and there were two positive selection loci. The catalytic capacity of AANAT in the Liaoning population that underwent positive selection was significantly higher than that of the Yunnan population (p < 0.05). This difference may be related to the lower proportion of α helix and the variation in two interface residues. The adaptive evolution of AANAT was significantly correlated with climate and environment (p < 0.05). After controlling for geographical factors (latitude and altitude), the evolution of AANAT by the negative temperature factor was represented by the monthly mean temperature (r = -0.6, p < 0.05). The results identified the gene level variation, functional adaptation, and evolutionary driving factors of AANAT, provide an important foundation for further understanding the adaptive evolution of the single copy of AANAT in pteropods, and may offer evidence for adaptive hibernation rhythms in bats.
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Affiliation(s)
- Yanhui Zhao
- Jilin Provincial Key Laboratory of Animal Resource Conservation and Utilization, Northeast Normal University, Changchun 130117, China; (Y.Z.); (Y.P.); (J.F.)
- Key Laboratory of Vegetation Ecology, Ministry of Education, Changchun 130024, China
| | - Lei Wang
- School of Water Conservancy & Environment Engineering, Changchun Institute of Technology, Changchun 130012, China;
| | - Sen Liu
- College of Life Sciences, Henan Normal University, Xinxiang 453007, China;
| | - Yingting Pu
- Jilin Provincial Key Laboratory of Animal Resource Conservation and Utilization, Northeast Normal University, Changchun 130117, China; (Y.Z.); (Y.P.); (J.F.)
- Key Laboratory of Vegetation Ecology, Ministry of Education, Changchun 130024, China
| | - Keping Sun
- Jilin Provincial Key Laboratory of Animal Resource Conservation and Utilization, Northeast Normal University, Changchun 130117, China; (Y.Z.); (Y.P.); (J.F.)
- Key Laboratory of Vegetation Ecology, Ministry of Education, Changchun 130024, China
| | - Yanhong Xiao
- Jilin Provincial Key Laboratory of Animal Resource Conservation and Utilization, Northeast Normal University, Changchun 130117, China; (Y.Z.); (Y.P.); (J.F.)
| | - Jiang Feng
- Jilin Provincial Key Laboratory of Animal Resource Conservation and Utilization, Northeast Normal University, Changchun 130117, China; (Y.Z.); (Y.P.); (J.F.)
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Suriagandhi V, Nachiappan V. Protective Effects of Melatonin against Obesity-Induced by Leptin Resistance. Behav Brain Res 2022; 417:113598. [PMID: 34563600 DOI: 10.1016/j.bbr.2021.113598] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2021] [Revised: 09/01/2021] [Accepted: 09/21/2021] [Indexed: 12/20/2022]
Abstract
Consumption of an exceedingly high-fat diet with irregular eating and sleeping habits is typical in the current sedentary lifestyle, leading to chronic diseases like obesity and diabetes mellitus. Leptin is a primary appetite-regulating hormone that binds to its receptors in the hypothalamic cell membrane and regulates downstream appetite-regulating neurons NPY/AgRp and POMC in the hypothalamus. Based on the fat content of the adipose tissue, leptin is secreted, and excess accumulation of fat in adipose tissue stimulates the abnormal secretion of leptin. The secreted leptin circulating in the bloodstream uses its transporters to cross the blood-brain barrier (BBB) and reach the CSF. There is a saturation limit for leptin bound to its transporters to cross the BBB, and increased leptin secretion in adipose tissue has a defect in its transport across the BBB. Leptin resistance is due to excess leptin, a saturation of its transporters, and deficiency in either the receptor level or signalling in the hypothalamus. Leptin resistance leads to obesity due to excess food intake and less energy expenditure. Normal leptin secretion follows a rhythm, and alteration in the lifestyle leads to hormonal imbalances and increases ROS generation leading to oxidative stress. The sleep disturbance causes obesity with increased lipid accumulation in adipose tissue. Melatonin is the master regulator of the sleep-wake cycle secreted by the pineal gland during the night. It is a potent antioxidant with anti-inflammatory properties. Melatonin is secreted in a pattern called the circadian rhythm in humans as well. Research indicates that melatonin plays a vital role in hormonal regulation and energy metabolism, including leptin signalling and secretion. Studying the role of melatonin in leptin regulation will help us combat the pathologies of obesity caused by leptin resistance.
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Affiliation(s)
- Vennila Suriagandhi
- Biomembrane Lab, Department of Biochemistry, School of Life Sciences, Bharathidasan University, Tiruchirappalli 620024, Tamilnadu, India
| | - Vasanthi Nachiappan
- Biomembrane Lab, Department of Biochemistry, School of Life Sciences, Bharathidasan University, Tiruchirappalli 620024, Tamilnadu, India.
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Ajit K, Murphy BD, Banerjee A. Elucidating evolutionarily conserved mechanisms of diapause regulation using an in silico approach. FEBS Lett 2021; 595:1350-1374. [PMID: 33650678 DOI: 10.1002/1873-3468.14064] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Revised: 02/02/2021] [Accepted: 02/19/2021] [Indexed: 11/11/2022]
Abstract
Embryonic diapause is an enigmatic phenomenon that appears in diverse species. Although regulatory mechanisms have been established, there is much to be discovered. Herein, we have made the first comprehensive attempt to elucidate diapause regulatory mechanisms using a computational approach. We found transcription factors unique to promoters of genes in diapause species. From pathway analysis and STRING PPI networks, the signaling pathways regulated by these unique transcription factors were identified. The pathways were then consolidated into a model to combine various known mechanisms of diapause regulation. This work also highlighted certain transcription factors that may act as 'master transcription factors' to regulate the phenomenon. Promoter analysis further suggested evidence for independent evolution for some of regulatory elements involved in diapause.
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Affiliation(s)
- Kamal Ajit
- Department of Biological Sciences, BITS Pilani KK Birla Goa Campus, Goa, India
| | - Bruce D Murphy
- Centre de Recherche en Reproduction et Fertilité, Faculté de Médicine Vétérinaire, Université Montréal, St-Hyacinthe, QC, Canada
| | - Arnab Banerjee
- Department of Biological Sciences, BITS Pilani KK Birla Goa Campus, Goa, India
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Lazzeroni ME, Burbrink FT, Simmons NB. Hibernation in bats (Mammalia: Chiroptera) did not evolve through positive selection of leptin. Ecol Evol 2018; 8:12576-12596. [PMID: 30619566 PMCID: PMC6308895 DOI: 10.1002/ece3.4674] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2018] [Revised: 09/10/2018] [Accepted: 09/14/2018] [Indexed: 01/25/2023] Open
Abstract
Temperature regulation is an indispensable physiological activity critical for animal survival. However, relatively little is known about the origin of thermoregulatory regimes in a phylogenetic context, or the genetic mechanisms driving the evolution of these regimes. Using bats as a study system, we examined the evolution of three thermoregulatory regimes (hibernation, daily heterothermy, and homeothermy) in relation to the evolution of leptin, a protein implicated in regulation of torpor bouts in mammals, including bats. A threshold model was used to test for a correlation between lineages with positively selected lep, the gene encoding leptin, and the thermoregulatory regimes of those lineages. Although evidence for episodic positive selection of lep was found, positive selection was not correlated with lineages of heterothermic bats, a finding that contradicts results from previous studies. Evidence from our ancestral state reconstructions suggests that the most recent common ancestor of bats used daily heterothermy and that the presence of hibernation is highly unlikely at this node. Hibernation likely evolved independently at least four times in bats-once in the common ancestor of Vespertilionidae and Molossidae, once in the clade containing Rhinolophidae and Rhinopomatidae, and again independently in the lineages leading to Taphozous melanopogon and Mystacina tuberculata. Our reconstructions revealed that thermoregulatory regimes never transitioned directly from hibernation to homeothermy, or the reverse, in the evolutionary history of bats. This, in addition to recent evidence that heterothermy is best described along a continuum, suggests that thermoregulatory regimes in mammals are best represented as an ordered continuous trait (homeothermy ← → daily torpor ← → hibernation) rather than as the three discrete regimes that evolve in an unordered fashion. These results have important implications for methodological approaches in future physiological and evolutionary research.
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Affiliation(s)
| | - Frank T. Burbrink
- Division of Vertebrate Zoology, Department of HerpetologyAmerican Museum of Natural HistoryNew YorkNew York
| | - Nancy B. Simmons
- Division of Vertebrate Zoology, Department of MammalogyAmerican Museum of Natural HistoryNew YorkNew York
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Nduhirabandi F, Huisamen B, Strijdom H, Lochner A. Role of melatonin in glucose uptake by cardiomyocytes from insulin-resistant Wistar rats. Cardiovasc J Afr 2017; 28:362-369. [PMID: 28556852 PMCID: PMC5885054 DOI: 10.5830/cvja-2017-018] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2016] [Accepted: 04/04/2017] [Indexed: 12/31/2022] Open
Abstract
Aim Melatonin supplementation reduces insulin resistance and protects the heart in obese rats. However, its role in myocardial glucose uptake remains unknown. This study investigated the effect of short-term melatonin treatment on glucose uptake by cardiomyocytes isolated from obese and insulin-resistant rats. Methods Cardiomyocytes were isolated from obese rats fed a high-calorie diet for 16 to 23 weeks, their age-matched controls, as well as young control rats aged four to eight weeks. After incubation with melatonin with or without insulin, glucose uptake was initiated by the addition of 2-deoxy-D-[3H] glucose and measured after 30 minutes. Additional control and obese rats received melatonin in the drinking water (4 mg/kg/day) for the last six weeks of feeding (20 weeks) and glucose uptake was determined in isolated cardiomyocytes after incubation with insulin. Intraperitoneal glucose tolerance and biometric parameters were also measured. Results Obese rats (fed for more than 20 weeks) developed glucose intolerance. Cardiomyocytes isolated from these obese rats had a reduced response to insulin-stimulated glucose uptake (ISGU) (p < 0.05). Melatonin administration in vitro had no effect on glucose uptake per se. However, it increased ISGU by cardiomyocytes from the young rats (p < 0.05), while having no effect on ISGU by cardiomyocytes from the older control and obese groups. Melatonin in vivo had no significant effect on glucose tolerance, but it increased basal (p < 0.05) and ISGU by cardiomyocytes from the obese rats (50.1 ± 1.7 vs 32.1 ± 5.1 pmol/mg protein/30 min, p < 0.01). Conclusion These data suggest that short-term melatonin treatment in vivo but not in vitro improved glucose uptake and insulin responsiveness of cardiomyocytes in obesity and insulin-resistance states.
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Affiliation(s)
- Frederic Nduhirabandi
- Division of Medical Physiology, Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Stellenbosch University, South Africa.
| | - Barbara Huisamen
- Division of Medical Physiology, Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Stellenbosch University, South Africa; Biotechnology, Research and Innovation Platform, South African Medical Research Council, Tygerberg, South Africa
| | - Hans Strijdom
- Division of Medical Physiology, Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Stellenbosch University, South Africa
| | - Amanda Lochner
- Division of Medical Physiology, Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Stellenbosch University, South Africa
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Baltaci AK, Mogulkoc R. Leptin, NPY, Melatonin and Zinc Levels in Experimental Hypothyroidism and Hyperthyroidism: The Relation to Zinc. Biochem Genet 2017; 55:223-233. [PMID: 28097455 DOI: 10.1007/s10528-017-9791-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2016] [Accepted: 01/08/2017] [Indexed: 01/15/2023]
Abstract
Since zinc mediates the effects of many hormones or is found in the structure of numerous hormone receptors, zinc deficiency leads to various functional impairments in the hormone balance. And also thyroid hormones have important activity on metabolism and feeding. NPY and leptin are affective on food intake and regulation of appetite. The present study is conducted to determine how zinc supplementation and deficiency affect thyroid hormones (free and total T3 and T4), melatonin, leptin, and NPY levels in thyroid dysfunction in rats. The experiment groups in the study were formed as follows: Control (C); Hypothyroidism (PTU); Hypothyroidism+Zinc (PTU+Zn); Hypothyroidism+Zinc deficient; Hyperthyroidism (H); Hyperthyroidism+Zinc (H+Zn); and Hyperthyroidism+Zinc deficient. Thyroid hormone parameters (FT3, FT4, TT3, and TT4) were found to be reduced in hypothyroidism groups and elevated in the hyperthyroidism groups. Melatonin values increased in hyperthyroidism and decreased in hypothyroidism. Leptin and NPY levels both increased in hypo- and hyperthyroidism. Zinc levels, on the other hand, decreased in hypothyroidism and increased in hyperthyroidism. Zinc supplementation, particularly when thyroid function is impaired, has been demonstrated to markedly prevent these changes.
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Affiliation(s)
| | - Rasim Mogulkoc
- Medical School, Department of Physiology, Selcuk University, Konya, Turkey.
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de Luxán-Delgado B, Potes Y, Rubio-González A, Caballero B, Solano JJ, Fernández-Fernández M, Bermúdez M, Rodrigues Moreira Guimarães M, Vega-Naredo I, Boga JA, Coto-Montes A. Melatonin reduces endoplasmic reticulum stress and autophagy in liver of leptin-deficient mice. J Pineal Res 2016; 61:108-23. [PMID: 27090356 DOI: 10.1111/jpi.12333] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/05/2016] [Accepted: 04/12/2016] [Indexed: 12/17/2022]
Abstract
The sedentary lifestyle of modern society along with the high intake of energetic food has made obesity a current worldwide health problem. Despite great efforts to study the obesity and its related diseases, the mechanisms underlying the development of these diseases are not well understood. Therefore, identifying novel strategies to slow the progression of these diseases is urgently needed. Experimental observations indicate that melatonin has an important role in energy metabolism and cell signalling; thus, the use of this molecule may counteract the pathologies of obesity. In this study, wild-type and obese (ob/ob) mice received daily intraperitoneal injections of melatonin at a dose of 500 μg/kg body weight for 4 weeks, and the livers of these mice were used to evaluate the oxidative stress status, proteolytic (autophagy and proteasome) activity, unfolded protein response, inflammation and insulin signalling. Our results show, for the first time, that melatonin could significantly reduce endoplasmic reticulum stress in leptin-deficient obese animals and ameliorate several symptoms that characterize this disease. Our study supports the potential of melatonin as a therapeutic treatment for the most common type of obesity and its liver-associated disorders.
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Affiliation(s)
- Beatriz de Luxán-Delgado
- Department of Morphology and Cellular Biology, Faculty of Medicine, University of Oviedo, Oviedo, Spain
| | - Yaiza Potes
- Department of Morphology and Cellular Biology, Faculty of Medicine, University of Oviedo, Oviedo, Spain
| | - Adrian Rubio-González
- Department of Morphology and Cellular Biology, Faculty of Medicine, University of Oviedo, Oviedo, Spain
| | - Beatriz Caballero
- Department of Morphology and Cellular Biology, Faculty of Medicine, University of Oviedo, Oviedo, Spain
| | | | | | | | - Marcela Rodrigues Moreira Guimarães
- Department of Morphology and Cellular Biology, Faculty of Medicine, University of Oviedo, Oviedo, Spain
- Neurology, Laboratory of Nutritional Investigation and Degenerative-Chronic Diseases (LINDCD), Federal University of Rio de Janeiro State - UNIRIO, Rio de Janeiro, Brazil
| | - Ignacio Vega-Naredo
- Department of Morphology and Cellular Biology, Faculty of Medicine, University of Oviedo, Oviedo, Spain
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, Cantanhede, Portugal
| | - José Antonio Boga
- Microbiology Department, Hospital Universitario Central de Asturias, Asturias, Oviedo, Spain
| | - Ana Coto-Montes
- Department of Morphology and Cellular Biology, Faculty of Medicine, University of Oviedo, Oviedo, Spain
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Xiong XQ, Chen WW, Zhu GQ. Adipose afferent reflex: sympathetic activation and obesity hypertension. Acta Physiol (Oxf) 2014; 210:468-78. [PMID: 24118791 DOI: 10.1111/apha.12182] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2013] [Revised: 08/05/2013] [Accepted: 10/09/2013] [Indexed: 01/09/2023]
Abstract
Excessive sympathetic activity contributes to the pathogenesis of hypertension and the progression of the related organ damage. Adipose afferent reflex (AAR) is a sympatho-excitatory reflex that the afferent activity from white adipose tissue (WAT) increases sympathetic outflow and blood pressure. Hypothalamic paraventricular nucleus (PVN or PVH) is one of the central sites in the control of the AAR, and ionotropic glutamate receptors in the nucleus mediate the AAR. The AAR is enhanced in obesity and obesity hypertension. Enhanced WAT afferent activity and AAR contribute to the excessive sympathetic activation and hypertension in obesity. Blockage of the AAR attenuates the excessive sympathetic activity and hypertension. Leptin may be one of sensors in the WAT for the AAR, and is involved in the enhanced AAR in obesity and hypertension. This review focuses on the neuroanatomical basis and physiological functions of the AAR, and the important role of the enhanced AAR in the pathogenesis of obesity hypertension.
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Affiliation(s)
- X.-Q. Xiong
- Key Laboratory of Cardiovascular Disease and Molecular Intervention; Department of Physiology; Nanjing Medical University; Nanjing 210029 China
| | - W.-W. Chen
- Key Laboratory of Cardiovascular Disease and Molecular Intervention; Department of Physiology; Nanjing Medical University; Nanjing 210029 China
| | - G.-Q. Zhu
- Key Laboratory of Cardiovascular Disease and Molecular Intervention; Department of Physiology; Nanjing Medical University; Nanjing 210029 China
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Natural selection and adaptive evolution of leptin. CHINESE SCIENCE BULLETIN-CHINESE 2013. [DOI: 10.1007/s11434-012-5635-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Levin E, Yom-Tov Y, Hefetz A, Kronfeld-Schor N. Changes in diet, body mass and fatty acid composition during pre-hibernation in a subtropical bat in relation to NPY and AgRP expression. J Comp Physiol B 2012; 183:157-66. [DOI: 10.1007/s00360-012-0689-0] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2012] [Revised: 06/18/2012] [Accepted: 06/28/2012] [Indexed: 12/20/2022]
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Nduhirabandi F, du Toit EF, Lochner A. Melatonin and the metabolic syndrome: a tool for effective therapy in obesity-associated abnormalities? Acta Physiol (Oxf) 2012; 205:209-23. [PMID: 22226301 DOI: 10.1111/j.1748-1716.2012.02410.x] [Citation(s) in RCA: 84] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2011] [Revised: 09/20/2011] [Accepted: 01/04/2012] [Indexed: 12/20/2022]
Abstract
The metabolic syndrome (MetS) is a cluster of metabolic abnormalities associated with increased risk for cardiovascular diseases. Apart from its powerful antioxidant properties, the pineal gland hormone melatonin has recently attracted the interest of various investigators as a multifunctional molecule. Melatonin has been shown to have beneficial effects in cardiovascular disorders including ischaemic heart disease and hypertension. However, its role in cardiovascular risk factors including obesity and other related metabolic abnormalities is not yet established, particularly in humans. New emerging data show that melatonin may play an important role in body weight regulation and energy metabolism. This review will address the role of melatonin in the MetS focusing on its effects in obesity, insulin resistance and leptin resistance. The overall findings suggest that melatonin should be exploited as a therapeutic tool to prevent or reverse the harmful effects of obesity and its related metabolic disorders.
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Affiliation(s)
- F. Nduhirabandi
- Division of Medical Physiology; Department of Biomedical Sciences; Faculty of Health Sciences; Stellenbosch University; Stellenbosch; South Africa
| | - E. F. du Toit
- School of Medical Science; Griffith University; Southport; Australia
| | - A. Lochner
- Division of Medical Physiology; Department of Biomedical Sciences; Faculty of Health Sciences; Stellenbosch University; Stellenbosch; South Africa
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Roy VK, Krishna A. Regulation of leptin synthesis during adipogenesis in males of a vespertilionid bat, Scotophilus heathi. ACTA ACUST UNITED AC 2011; 214:1599-606. [PMID: 21490267 DOI: 10.1242/jeb.054973] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
The aim of this study was to elucidate the hormonal regulation of leptin synthesis by the white adipose tissue (WAT) during the period of fat accumulation in male Scotophilus heathi. An in vivo study showed a significant correlation between the seasonal changes in serum insulin level with the circulating leptin level and with the changes in body fat mass in S. heathi. An in vitro study showed insulin induced a significant increase in expression of leptin protein in WAT. The insulin-stimulated increase in leptin expression was associated with increased uptake of glucose in the WAT. Two glucose transporters (GLUT4 and GLUT8) are utilized for transport of glucose in the WAT during adipogenesis in the bat. The bats showed high insulin and glucose levels, but a reduction in insulin receptor protein during the period of fat deposition, suggesting insulin resistance, which improved in late winter (January) when most of the fat has been utilized as a metabolic fuel. The in vitro study confirmed that insulin enhanced leptin and GLUT4 expression in WAT. The in vitro study further showed that the expression of leptin is directly proportional to the amount of glucose uptake by the WAT. The expression of GLUT4 and GLUT8 were also shown to be differentially regulated by insulin during adipogenesis. The insulin-stimulated increase in leptin synthesis by WAT is mediated through phosphorylation of MAPK in S. heathi. The specific role of GLUT4 and GLUT8 in the regulation of leptin synthesis during adipogenesis needs further investigation.
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Affiliation(s)
- Vikas Kumar Roy
- Department of Zoology, Banaras Hindu University, Varanasi-221005, India
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