Animal Models of Obesity

Abstract

Animal models have played an important role in advancing our understanding of the causes and consequences of obesity. The spontaneous single gene mutations led to the discovery of leptin and the melanocortin signaling pathways and were important to the understanding of hypothalamic systems that control energy balance. The use of transgenic and gene targeting technologies has opened a new era of investigation, identifying new genes that regulate the development or prevention of obesity and providing the tools for proof of function of genes. These studies have shown that a wide range of genes expressed primarily in the central nervous system or in adipose tissue are potential targets for the treatment of obesity.

Morphological and biochemical alterations of skeletal muscles from the genetically obese (ob/ob) mouse

“…4,44 The shift towards a slower, more aerobic-oxidative phenotype observed in SM, EDL, and SOL muscles from obese mice might also be related to the higher level of circulating glucocorticoids in ob/ob mice. 5 Indeed, fibre type changes in the direction discussed above have been associated with elevated glucocorticoid concentrations. 30,45 For example, in EDL and plantaris of adult rat, elevated glucocorticoid concentrations lead to alterations that are similar to those obtained for SM and EDL from obese mice in this study, viz.…”

“…Elevated glucocorticoid levels play a key role in the development of obesity in rodent models 5 and are implicated in muscle atrophy. 30 In the ob/ob mouse, circulating levels of the glucocorticoid corticosterone are raised, 5 as is its sensitivity to the hormone.…”

“…30 In the ob/ob mouse, circulating levels of the glucocorticoid corticosterone are raised, 5 as is its sensitivity to the hormone. 31 In fact, when circulating Alterations in skeletal muscles of ob/ob mouse JG Kemp et al concentrations of corticosterone were lowered by adrenalectomy, ob/ob mice displayed improvements in muscle mass gain.…”

Dieta hiperlipídica com farinha de soja como fonte proteica: utilização na seleção de ratos propensos e resistentes à obesidade

“…Em experimentos realizados com ratos, foi observado que mesmo o emprego de uma dieta altamente palatável e energética não garante que todos animais se tornem obesos, pois muitos deles ganham peso como os animais controles, que são alimentados com dieta padrão [13][14][15] . A possível explicação está na evidência de que, também como ocorre entre homens, existem animais propensos e animais resistentes à obesidade [13][14][15] .…”

“…A possível explicação está na evidência de que, também como ocorre entre homens, existem animais propensos e animais resistentes à obesidade [13][14][15] . Esses achados têm levado os pesquisadores da obesidade a adotarem o modelo experimental que permite identificar animais propensos e resistentes à obesidade.…”