Inter-relação da leptina e dos hormônios tireoidianos na perda de peso de ratos obesos
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Data
2007-02-27
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Universidade Estadual Paulista (Unesp)
Resumo
A obesidade é uma doença crônica, multifatorial que leva ao aumento do risco de desenvolver outras doenças. É freqüentemente considerada como uma doença do estilo de vida, causada pela escolha errônea dos alimentos e pela diminuição da atividade física, sendo a restrição calórica a prática mais comum para tratar a obesidade. Em humanos, a perda de peso está associada com redução de fatores de risco para doenças cardiovasculares, diminuição da taxa de incidência de Diabetes Mellitus tipo 2 e aumento da qualidade de vida. O peso corporal é regulado por uma interação complexa entre hormônios e neuropeptídeos. A leptina e os hormônios tireoidianos (HT) estão envolvidos na regulação do balanço energético. Objetivo: Analisar, em ratos, a inter-relação entre leptina e hormônios tireoidianos na obesidade e na perda de peso. Metodologia: Foram utilizados ratos Wistar machos, com 30 dias de idade, separados em dois grupos, Controle (C) e Obeso (OB). Os animais C receberam ração comercial Labina e os do grupo OB um ciclo de dietas hipercalóricas por 15 semanas. Após o período de indução de obesidade, os animais OB foram novamente separados em outros 3 grupos, OB; animais com restrição alimentar (RIA); e animais com restrição mais administração de Hormônio Tireoidiano (RHT) na dose de 5 mg/100g de peso do animal. Os animais OB receberam as dietas hipercalóricas até o final do experimento, enquanto os animais RIA e RHT receberam 75% do total consumido pelo grupo C de dieta comercial, por 28 dias. Após este período, os animais RIA continuaram, somente, com a restrição alimentar e os RHT receberam além da restrição...
Obesity is a chronic multifactor disease which brings increased risk of developing other diseases. It is frequently considered as a lifestyle disease, caused by choosing the wrong foods and reducing physical activity, with calorie restriction being the commonest way of treating it. Weight loss in humans is associated with reduced risk factors for cardiovascular disease, reduced incidence of type II Diabetes Mellitus, and increased quality of life. Bodyweight is regulated by a complex interaction between hormones and neopeptides. Leptin and the thyroid hormones (TH) are involved in regulating the energy balance. Objective: To analyze the interrelation in rats between leptin and thyroid hormones in obesity and weight loss. Methodology: Male 30-day-old Wistar rats were separated into two groups, Control (C) and Obese (OB). Control animals received commercial Labina rat food and the OB group a cycle of hypercaloric diets for 15 weeks. After the induced obesity period, the OB animals were separated into three subgroups; OB hypercaloric diet; RIA food restriction; RHT food restriction plus 5mg/100g body weight thyroid hormone. OB animals received the hypercaloric diets until the end of the experiment, where the RIA and RHT animals received 75% the total commercial food consumed by the control group for 28 days. After this period, the RIA animals continued with food restriction only, and the RHT animals received food restriction plus a dose of TH for 28 days. At each phase of the experiment, five animals from each group were sacrificed to analyze gene expression of leptin and TRb in adipose tissue using semiquantitative RT-PCR. Results: The OB animals showed increased weight and adipose tissue, lipid and glycemia profile changes, and increased plasmatic... (Complete abstract click electronic access below)
Obesity is a chronic multifactor disease which brings increased risk of developing other diseases. It is frequently considered as a lifestyle disease, caused by choosing the wrong foods and reducing physical activity, with calorie restriction being the commonest way of treating it. Weight loss in humans is associated with reduced risk factors for cardiovascular disease, reduced incidence of type II Diabetes Mellitus, and increased quality of life. Bodyweight is regulated by a complex interaction between hormones and neopeptides. Leptin and the thyroid hormones (TH) are involved in regulating the energy balance. Objective: To analyze the interrelation in rats between leptin and thyroid hormones in obesity and weight loss. Methodology: Male 30-day-old Wistar rats were separated into two groups, Control (C) and Obese (OB). Control animals received commercial Labina rat food and the OB group a cycle of hypercaloric diets for 15 weeks. After the induced obesity period, the OB animals were separated into three subgroups; OB hypercaloric diet; RIA food restriction; RHT food restriction plus 5mg/100g body weight thyroid hormone. OB animals received the hypercaloric diets until the end of the experiment, where the RIA and RHT animals received 75% the total commercial food consumed by the control group for 28 days. After this period, the RIA animals continued with food restriction only, and the RHT animals received food restriction plus a dose of TH for 28 days. At each phase of the experiment, five animals from each group were sacrificed to analyze gene expression of leptin and TRb in adipose tissue using semiquantitative RT-PCR. Results: The OB animals showed increased weight and adipose tissue, lipid and glycemia profile changes, and increased plasmatic... (Complete abstract click electronic access below)
Descrição
Palavras-chave
Hormonios tireoidianos - Efeitos fisiológicos, Obesidade, Tireóide - Perda de peso, Thyroid hormones
Como citar
LUVIZOTTO, Renata de Azevedo Melo. Inter-relação da leptina e dos hormônios tireoidianos na perda de peso de ratos obesos. 2007. 83 f. Dissertação (mestrado) - Universidade Estadual Paulista, Faculdade de Medicina de Botucatu, 2007.