Molecular Mechanisms of Appetite Regulation

The prevalence of obesity has been rapidly increasing worldwide over the last several decades and has become a major health problem in developed countries. The brain, especially the hypothalamus, plays a key role in the control of food intake by sensing metabolic signals from peripheral organs and modulating feeding behaviors. To accomplish these important roles, the hypothalamus communicates with other brain areas such as the brainstem and reward-related limbic pathways. The adipocyte-derived hormone leptin and pancreatic beta-cell-derived insulin inform adiposity to the hypothalamus. Gut hormones such as cholecystokinin, peptide YY, pancreatic polypeptide, glucagon-like peptide 1, and oxyntomodulin transfer satiety signals to the brain and ghrelin relays hunger signals. The endocannabinoid system and nutrients are also involved in the physiological regulation of food intake. In this article, we briefly review physiological mechanisms of appetite regulation.

Oxintomodulina e obesidade / Oxyntomodulin and obesity

Desde o descobrimento da leptina, avanços consideráveis foram obtidos na caracterização dos mecanismos hipotalâmicos do controle da ingestão alimentar e, atualmente, a oxintomodulina é reconhecida como um regulador da homeostase energética. O presente artigo de revisão enfoca algumas das mais relevantes inter-relações do hormônio oxintomodulina com o apetite, a homeostase energética e aspectos de seu papel na bioquímica e fisiologia nutricional. A oxintomodulina é um peptídeo intestinal anorexígeno produzido pelas células L do intestino. Recentes estudos têm demonstrado que em longo prazo a administração de oxintomodulina reduz a ingestão alimentar e o ganho de peso. Pesquisas em humanos têm verificado que o seu uso reduz o consumo energértico em 25 por cento. Portanto, a oxintomodulina representa uma potente terapia anti-obesidade. Entretanto, o mecanismo de ação da oxintomodulina ainda é desconhecido. Atuais evidências sugerem que tem ação via receptor do peptídeo semelhante ao glucagon 1. Além disso, a literatura mostra que, juntamente com a adoção de hábitos saudáveis e a mudança do estilo de vida, a oxintomodulina pode proporcionar menor avanço da obesidade.

Since the discovery of leptin, great advances occurred in the characterization of hypothalamic mechanisms involved in the control of food intake and oxyntomodulin is currently recognized as a homeostasis energy regulator. This review discusses the most important interrelationships between the hormone oxyntomodulin and appetite, energy homeostasis and aspects of its role in nutritional biochemistry and physiology. Oxyntomodulin is an anorexigenic peptide produced by the L cells of the small intestine. Recent studies have shown that long-term use of oxyntomodulin in rats leads to reduced food intake and weight gain. Studies in humans have demonstrated that its administration reduces food intake by 25 percent. Therefore, oxyntomodulin represents a potent anti-obesity therapy. However, its mechanism of action is unknown. Current evidence suggests that it acts via the peptide receptor similar to glucagon 1. Moreover, the literature shows that together with the adoption of healthy habits and lifestyle changes, oxyntomodulin can reduce weight gain.

Expression of oxyntomodulin in bifidobacteria and effect of oxyntomodulin-transformed bifidobacteria on the body weight of obese mice / 南方医科大学学报

<p><b>OBJECTIVE</b>To observe the effect of pBBADs-OXM-transformed bifidobacteria on the body weight of obese mice.</p><p><b>METHODS</b>B. longum was transformed with pBBADs-OXM by electroporation, and arabopyranose-induced oxyntomodulin expression by the bacterium was detected by ELISA. pBBADs-OXM-transformed bifidobacteria was administered orally obese mice on a daily basis with pBBADs-GFP-transformed bifidobacteria as the negative control, and the body weight changes of the mice were observed.</p><p><b>RESULTS</b>OXM was detected by ELISA not only in the supernatant but also the precipitant of the transformed bacterial culture. The body weight of the obese mice fed with pBBADs-OXM-transformed bifidobacteria decreased significantly compared with that of the mice in the obese model group (P<0.05).</p><p><b>CONCLUSION</b>Administration of pBBADs-OXM-transformed B.longum can reduce the body weight of obese mice.</p>