HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) All Versions of this Article: 285/3/R594    most recent 00748.2002v1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in ISI Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via ISI Web of Science (31) Citing Articles via Google Scholar Google Scholar Articles by Breuner, C. W. Articles by Wingfield, J. C. Search for Related Content PubMed PubMed Citation Articles by Breuner, C. W. Articles by Wingfield, J. C.

COMPLEX FUNCTION OF THE CENTRAL NERVOUS SYSTEM, SLEEP AND LOCOMOTION

Differential mechanisms for regulation of the stress response across latitudinal gradients

¹Integrative Biology, University of Texas, Austin, Texas 78712; ²Department of Biology, Arizona State University, Tempe, Arizona 85287; ³Department of Zoology, University of Washington, Seattle, Washington 98915; ⁴Neurobiology, Physiology, and Behavior, University of California, Davis, California 95616; and ⁵Division of Biomedical and Clinical Laboratory Sciences, University of Edinburgh Medical School, Edinburgh EH8 9XD, Scotland, United Kingdom

Submitted 9 December 2002 ; accepted in final form 18 May 2003

We examined plasticity of the stress response among three populations of the white-crowned sparrow (Zonotrichia leucophrys). These populations breed at different elevations and latitudes and thus have breeding seasons that differ markedly in length. We hypothesize that in populations where birds raise only one or rarely two broods in a season, the fitness costs of abandoning a nest are substantially larger than in closely related populations that raise up to three broods per season. Thus individuals with short breeding seasons should be less responsive to stressors and therefore less likely to abandon their young. In our study, baseline and handling-induced corticosterone levels were similar among populations, but corticosteroid-binding globulins differed, leading to a direct relationship between stress-induced free corticosteroid levels and length of breeding season. There were also population-specific differences in intracellular low-affinity (glucocorticoid-like) receptors in both liver and brain tissue. Although investigations of population-based differences in glucocorticoid secretion are common, this is the first study to demonstrate population-level differences in binding globulins. These differences could lead to dramatically different physiological and behavioral responses to stress.

white-crowned sparrow; corticosterone; corticosteroid-binding globulin; corticosteroid receptor; reproduction