The present review provides a comparative insight into structure, function and control of leptin system in fishes, herptiles, birds and mammals. In general, leptin acts as an anorexigenic hormone since its administration results in decrease of food intake in vertebrates. Nonetheless, functional paradox arises in fishes from contradictory observations on level of leptin during fasting and re-feeding. In addition, leptin is shown to modulate metabolic functions in fishes, reptiles, birds and mammals. Leptin also regulates reproductive and immune functions though more studies are warranted in non-mammalian vertebrates. The expression of leptin and its receptor is influenced by numerous factors including sex steroids, stress and stress-induced catecholamines and glucocorticoids though their effect in non-mammalian vertebrates is hard to be generalized due to limited studies.

本综述提供了对鱼类、爬虫类、鸟类和哺乳动物瘦素系统结构、功能和控制的比较洞察。一般来说，瘦素是一种厌食激素，因为它的给药会导致脊椎动物食物摄入量的减少。尽管如此，由于在禁食和再喂食期间对瘦素水平的矛盾观察，鱼类出现了功能悖论。此外，瘦素可调节鱼类、爬行动物、鸟类和哺乳动物的代谢功能。瘦素还调节生殖和免疫功能，尽管需要在非哺乳动物脊椎动物中进行更多研究。瘦素及其受体的表达受多种因素影响，包括性类固醇、