Creagh Breuner

creagh breunerI think about glucocorticoids from both  mechanistic and fitness viewpoints. 

Glucocorticoids regulate physiology and behavior such that an animal conserves energy to face the current challenge; these effects are thought to increase self-maintenance at the cost of current reproductive effort.  So I am interested in the role glucocorticoids play in this tradeoff, and how that role changes across life-history strategies.

Mechanistically, glucocorticoids enter the blood from the adrenal, and circulate bound to plasma glycoprotiens, corticosteroid binding globulins (CBG).  CBG may hold GCs in the plasma, to limit access to tissues and maintain a store of hormone in the blood (the free hormone hypothesis), or they may simply deliver GCs straight to tissues.  We are currently testing the free, bound, and total hormone hypotheses, evaluating which fraction may be the most biologically relevant immediately, and over time as stressors persist.


Graduate Students

Sarah Berk holding a bluebird

Sara Berk

Sara is doing her PhD in the Organismal Biology and Ecology program, focusing on glucocorticoids as global regulators of survival/reproduction tradeoffs in Mountain Bluebirds.

Devin Landry

Devin is doing his Master's Degree in the Wildlife Biology Program, focusing on the disturbance potential of aircraft at backcountry landing strips.