title: Leptin as a physiological mediator of energetic trade-offs in ecoimmunology: implications for disease.
abstract: Organisms must distribute sufficient energy among different and often competing physiological systems. This task can become challenging, however, as resources are often limiting, resulting in energetic trade-offs. For example, energetically based trade-offs between the reproductive and immune systems are common across taxa, yet the regulatory mechanisms underlying these trade-offs remain unclear. The adipose tissue hormone leptin is an ideal candidate for the modulation of energetic trade-offs between different physiological systems as this hormone serves as a gage of fat reserves and also modulates a range of physiological activities including the reproductive and immune processes. This article presents a review of the evidence for the role of leptin as a modulator of energetic trade-offs with the immune system and suggests its importance in disease ecology. In addition, we provide a case study of the ornate tree lizard (Urosaurus ornatus), testing whether leptin is involved in mediating a well-documented influence of energy state on the trade-off between reproductive activity and immune function. Overall, the combined results suggest that leptin serves as a proximate endocrine signal of available energy to the immune system, and therefore likely to affect susceptibility to diseases.
authors.affiliation: Department of Biology, Utah State University, Logan, UT 84322-5305, USA. sfrench@biology.usu.edu
authors.forename: Susannah S
authors.initials: SS
authors.lastname: French
authors.forename: M Denise
authors.initials: MD
authors.lastname: Dearing
authors.forename: Gregory E
authors.initials: GE
authors.lastname: Demas
mesh_terms: D000820:Animal Diseases / Q000276:immunology / Q000503:physiopathology; D000818:Animals; D004734:Energy Metabolism; D007107:Immune System / Q000502:physiology*; D020738:Leptin / Q000378:metabolism*; D008116:Lizards / Q000276:immunology* / Q000502:physiology*; D012098:Reproduction
chemical_list: D020738:Leptin