Meeting Abstract

P3-82   -    Does PPARγ Regulate Migratory Adiposity? Valachovic, AC*; Schaeffer, PJ; Miami University, Oxford Ohio; Miami University, Oxford Ohio valachac@miamioh.edu

The incredible endurance capacity of avian migration has fascinated scientists for centuries but work studying the physiological mechanisms that allow birds to accumulate fat for migration has further sparked research. The Gray Catbird (Dumetella carolinesis) is a good model to study migratory physiology because of the distinct life-history cycles they exhibit during migration. Conceptually, life-history tradeoffs around migration and adipose accumulation are not new, but questions remain regarding the regulation of life history transitions. One such possible mechanism for adipose changes is PPARγ. Transcription of genes regulating lipid metabolism are stimulated when fatty acids bind with PPAR. No study has looked at the role of PPARγ in the regulation of adipose accumulation and mobilization in the migratory and nonmigratory phenotype. We hypothesize that PPARγ activity is necessary to prepare for migration and is sufficient to induce the migratory phenotype. We captured the birds in Oxford Ohio with mist nets. Catbirds were surgically implanted with Alzet osmotic pumps that either released a PPARγ agonist drug, given to birds in summer conditions or an PPARγ antagonist drug to birds in fall conditions. Two experiments were done, first in an animal care facility and, second, in aviaries to assess the contribution of light alone or other environmental factors on these effects. After 2 weeks, birds were euthanized and tissue samples of adipose, heart, gastrocnemius, liver, and pectoralis muscle were taken for further analysis. Preliminary research shows a large fat-build up in gray catbirds that experienced shorter day periods that mimic migratory conditions in comparison to longer summer days. Manipulation of PPAR activity will provide insight into the role of PPARγ in lipid metabolism and avian migration. This will provide valuable insight into improving our understanding of migration, metabolism, and energetics in birds.