Abstract
Although golden-mantled ground squirrels (GMGS, Callospermophilus lateralis) have long been used as laboratory animals, little is known about their physiology as wild-living animals under natural conditions. In examining hormone profiles of serum taken from wild-living GMGS during the euthermic (May–August) season, we found that post-hibernation levels of the orexigenic hormone ghrelin were low, and gradually increased through July and August (pre-hibernation). Females generally had higher concentrations of circulating ghrelin than did males, possibly reflecting the greater energy requirements imposed on them by pregnancy and lactation. Leptin concentrations were extremely low throughout the summer months, possibly reflecting the lean condition of field GMGS, particularly on their exit from hibernation in May. These data provide preliminary evidence that seasonal changes in energy-modulating hormones may be informed by different energy requirements inherent between the sexes.
This manuscript is derived from a thesis submitted to the Academic Faculty of Colorado State University in partial fulfillment of the requirements for the degree of Doctor of Philosophy.
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Acknowledgments
Thanks to Cara Ostrom, Kendra Burdett, Cassandra Gearhart, Jenna Bateman, Ashley Fenn, Thomas Barnett, Litto Suu, and Melanie Richter for help with trapping and data analysis, to Melanie Hoobler and Danielle Wantuck for help with ghrelin assays, and Susan Fried for performing leptin RIA. We also thank Denise Pearson of Fox Acres Country Club for allowing us to trap ground squirrels on their property. This work was supported by NIH R25DK067017 to GLF.
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Healy, J.E., Florant, G.L. (2012). Ghrelin, Leptin, and Fatty Acids in Free-Living Callospermophilus lateralis (Golden-Mantled Ground Squirrels). In: Ruf, T., Bieber, C., Arnold, W., Millesi, E. (eds) Living in a Seasonal World. Springer, Berlin, Heidelberg. https://doi.org/10.1007/978-3-642-28678-0_45
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DOI: https://doi.org/10.1007/978-3-642-28678-0_45
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