Development of hypothalamic obesity in growing rats

Remke, H; Wilsdorf, A.; Müller, Fr.

doi:10.1016/s0232-1513(88)80076-8

Cited by 29 publications

(18 citation statements)

References 19 publications

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“…4 Decreased body weight in these animals may be associated to decreased growth hormone (GH) levels, which was previously found in 30 day old MSG-treated rats. 38,39 Decreased plasma levels of both NEFA and glycerol as well as decreased adipose tissue lipolysis and HSL activity found in our MSG-treated rats also support such decreased GH levels, since these changes have been reported to occur in GH de®cient conditions in adults. 40 However, adipose tissue cellularity shows that adipocytes in our 1 month old MSG-rats are already enlarged, indicating that they are initiating the development of obesity of the hypertrophic type, as has also been shown to occur in MSGtreated mice.…”

Section: Discussionsupporting

confidence: 69%

Decreased lipolysis and enhanced glycerol and glucose utilization by adipose tissue prior to development of obesity in monosodium glutamate (MSG) treated-rats

et al. 2001

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OBJECTIVE:To determine the metabolic alterations that lead to the neonatal administration of monosodium glutamate (MSG), which results in arrested growth and obesity. ANIMALS AND DESIGN: Wistar rats were injected 5 times, every other day, with 4 g of MSGakg b.w. or with hyperosmotic saline (controls), within the ®rst 10 days of life, and were studied at the age of 30 days. RESULTS: Body weight was lower, whereas adipocyte lipid content, cell diameter, surface area and volume were higher in MSG rats than in controls. Plasma glucose, insulin, NEFA, glycerol and triglyceride levels, and in vitro production of NEFA by lumbar fat pad pieces incubated under basal conditions or in the presence of epinephrine and epinephrine plus glucose in the media were lower in MSG than in control rats. In the same fat pad pieces, the conversion of 1-14 C-glycerol into fatty acids was always enhanced and its conversion into glyceride glycerol was enhanced when incubations were carried out in the presence of epinephrine or glucose. Both the hormone sensitive lipase activity and mRNA expression were lower in adipose tissue from MSG rats. Besides, the number of insulin receptors, lipid synthesis from U 14 C glucose, 3 H-2-deoxy D-glucose uptake and cellular GLUT4 translocation index were higher in adipocytes from MSG rats than from the controls. CONCLUSION: It is proposed that an enhanced insulin sensitivity in 1 month old MSG rats is responsible for the decreased lipolytic activity and enhanced glucose uptake. In addition, the enhanced lipogenesis and glycerol reutilization seen in their adipose tissue, disturbs the normal balance between fat depots breakdown and accumulation in favor of the latter.

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Section: Discussionsupporting

confidence: 69%

Decreased lipolysis and enhanced glycerol and glucose utilization by adipose tissue prior to development of obesity in monosodium glutamate (MSG) treated-rats

et al. 2001

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“…The onset of obesity is associated with low sympathetic and high parasympathetic activities to sustain the accumulation of energy sources, such as fat tissue, decreasing catabolism, and increasing anabolism. Regarding the BW of MSG rats, we observed that they were lighter than respective control animals, which was the characteristic phenotype of this model as described by Remke et al (1988), Dolnikoff et al (2001), and Schoelch et al (2002). Although there were no overweight rats, the MSG-obese rats were found to have more fat pad stores as compared with control animals (Bernardis & Patterson 1968, Bray & York 1998, which was correlated with lower growth hormone (Bakke et al 1978, Acs et al 1982 and reduced basal metabolic rate (Arndt et al 1991).…”

Section: Discussionmentioning

confidence: 67%

HPA axis and vagus nervous function are involved in impaired insulin secretion of MSG-obese rats

Miranda

Torrezan

Oliveira

et al. 2016

Journal of Endocrinology

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Neuroendocrine dysfunctions such as the hyperactivity of the vagus nerve and hypothalamus–pituitary–adrenal (HPA) axis greatly contribute to obesity and hyperinsulinemia; however, little is known about these dysfunctions in the pancreatic β-cells of obese individuals. We used a hypothalamic-obesity model obtained by neonatal treatment with monosodiuml-glutamate (MSG) to induce obesity. To assess the role of the HPA axis and vagal tonus in the genesis of hypercorticosteronemia and hyperinsulinemia in an adult MSG-obese rat model, bilateral adrenalectomy (ADX) and subdiaphragmatic vagotomy (VAG) alone or combined surgeries (ADX–VAG) were performed. To study glucose-induced insulin secretion (GIIS) and the cholinergic insulinotropic process, pancreatic islets were incubated with different glucose concentrations with or without oxotremorine-M, a selective agonist of the M3muscarinic acetylcholine receptor (M3AChR) subtype. Protein expression of M3AChR in pancreatic islets, corticosteronemia, and vagus nerve activity was also evaluated. Surgeries reduced 80% of the body weight gain. Fasting glucose and insulin were reduced both by ADX and ADX–VAG, whereas VAG was only associated with hyperglycemia. The serum insulin post-glucose stimulation was lower in all animals that underwent an operation. Vagal activity was decreased by 50% in ADX rats. In the highest glucose concentration, both surgeries reduced GIIS by 50%, whereas ADX-VAG decreased by 70%. Additionally, M3AChR activity was recovered by the individual surgeries. M3AChR protein expression was reduced by ADX. Both the adrenal gland and vagus nerve contribute to the hyperinsulinemia in the MSG model, although adrenal is more crucial as it appears to modulate parasympathetic activity and M3AChR expression in obesity.

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“…Por outro lado, devido à característica extenuante do teste de lactato mínimo durante a indução da lactacidemia, o protocolo parece muito agressivo para as condições físicas dos animais tratados com MSG. Mesmo assim, os autores verificaram que, para uma mesma carga de trabalho, os animais obesos realizaram menor esforço em comparação com o grupo controle (22) . Os achados de Voltarelli et al (8) corroboram os dados do presente estudo, no qual a MFEL encontrada nos grupos obesos, macho e fêmea, foi mais elevada (6% do PC) que nos grupos controles: 5% do PC para as fêmeas e 4,5% para os machos.…”

Section: Discussionunclassified

Máxima Fase estável de lactato em ratos obesos de ambos os gêneros

Araújo

D'Angelo

et al. 2009

Rev Bras Med Esporte

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A incidência de obesidade vem crescendo entre a população mundial, levando a inúmeras complicaçõe,s como risco de doenças crônico-degenerativas. Por outro lado, o exercício físico tem sido empregado isoladamente ou em associação a dieta, no tratamento dessa doença. Assim, pesquisas envolvendo exercício são imprescindíveis para evolução no tratamento e controle da obesidade. O objetivo deste estudo foi identificar a intensidade de exercício equivalente à transição metabólica aeróbio-anaeróbia em ratos Wistar obesos de ambos os gêneros, por tratamento com glutamato monossódico (MSG), utilizando o protocolo de máxima fase estável de lactato (MFEL). Para isso, foram testados 40 ratos adultos subdivididos em quatro grupos com 10 animais cada um: controle machos, controle fêmeas, obeso machos e obeso fêmeas. Depois de adequada adaptação (três semanas) ao exercício em meio líquido (31 ± 1ºC) os animais foram submetidos a teste de natação (25 min) suportando sobrecargas contínua e aleatória correspondentes a 4,5 -5,0 -5,5 -6,0 e 6,5% do peso corporal (PC), com intervalo de 72 horas entre elas. Os animais dos grupos obesos tiveram aumentos no peso do tecido adiposo subcutâneo, mesentérico e retroperitonial em relação aos grupos controle. O índice de Lee foi maior nos animais obesos em comparação com os controles. Foi possível identificar a MFEL a 6,0% do PC nos dois grupos obesos. Para o grupo controle fêmea, a MFEL esteve por volta de 5,0% do PC enquanto que nos controle macho a 4,5% do PC. Desse modo pode-se concluir que a obesidade induzida por MSG interfere na cinética de lactato durante o exercício em ambos os sexos, alterando a intensidade de esforço referente à transição metabólica.Palavras-chave: obesidade, capacidade aeróbia, hipotálamo. ABstrActThe purpose of this study was to identify the exercise intensity equivalent to the aerobic/anaerobic metabolic transition in obese rats of both genders using the maximal lactate steady state (MLSS) protocol. Four groups of rats were tested on MLSS protocol (swimming exercise): male control n=10, female control n=10, male obese n=10 and female obese n=10, after suitable adaptation to exercise in liquid medium and obesity induction by monossodic glutamate (MSG) administration. The obese groups had significant increase in subcutaneous adipose tissue as well as mesenteric and retroperitoneal fat depots comparing to the control groups. The Lee index was higher in the obese animals in comparison to their respective controls. It was possible to identify the MLSS at 6.0% of body weight for both obese groups. Concerning the female control group, the MLSS was determined at the intensity of 5.0% of body weight, whereas for the male control at 4.5% of body weight. It was concluded that obesity induced by MSG interferes in lactate kinetics during exercise and alters the effort intensity corresponding to the metabolic transition in both genders.Keywords: obesity, aerobic capacity, hypothalamus. introdUÇÃo A obesidade é provavelmente uma das enfermidades mais antigas que acometem o hom...

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Development of hypothalamic obesity in growing rats

Cited by 29 publications

References 19 publications

Decreased lipolysis and enhanced glycerol and glucose utilization by adipose tissue prior to development of obesity in monosodium glutamate (MSG) treated-rats

Decreased lipolysis and enhanced glycerol and glucose utilization by adipose tissue prior to development of obesity in monosodium glutamate (MSG) treated-rats

HPA axis and vagus nervous function are involved in impaired insulin secretion of MSG-obese rats

Máxima Fase estável de lactato em ratos obesos de ambos os gêneros

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