DOI: 10.5061/dryad.nzs7h450z
title: Data from:Unpredictable warm spells in winter increase blood cortisol level but lengthen telomeres in a seasonal rodent Phodopus sungorus

description: Animal performance in the environment significantly determines its
 fitness. However, global warming and the increased frequency of
 unpredictable weather events may disrupt the proper timing of seasonal
 adjustments of a phenotype. This may lead to the deterioration of the
 animal's condition and shorten its lifespan. We tested whether warm
 spells in winter affect the baseline and stress-induced cortisol level and
 leukocyte relative telomere length in two winter phenotypes of Siberian
 hamster Phodopus sungorus, responding and non-responding to short
 photoperiod. We found that both phenotypes increased cortisol levels in
 winter and that warm spells augmented this response. Under stable cold
 conditions, non-responding individuals were more vulnerable to short-term
 stress than responding ones. However, telomere length increased,
 suggesting that animals have a high potential to cope with stress and
 prevent telomere shortening or that these two variables are not directly
 related. In responding individuals, the higher incidence of torpor also
 prevented telomere shortening. These results indicate that both
 phenotypes, responding and non-responding to short photoperiod, can
 overcome the challenges posed by an unpredictably changing environment.
description: We used 230 Siberian hamsters (<em>Phodopus
 sungorus</em>) of both sexes: 120 (55 males and 65 females) for
 relative telomere length study (“RTL group’) and 110 animals (55 males and
 55 females) for cortisol and testosterone measurements (“CORT/T group”). 
 A hamster was classified as a responder if it turned white (at least stage
 2 or 3 of winter fur according to the Figala scale (Figala et al. 1973))
 and used daily torpor (at least one episode). Cortisol
 and testosterone concentrations were measured using liquid
 chromatography/tandem mass spectrometry (LC-MS-MS).
 Relative telomere length (RTL) was measured using the
 quantitative polymerase chain reaction (qPCR) approach.
description: # **Unpredictable warm spells in winter increase blood cortisol level but
 lengthen telomeres in a seasonal rodent *Phodopus sungorus***
 [https://doi.org/10.5061/dryad.nzs7h450z](https://doi.org/10.5061/dryad.nzs7h450z) ## Description of the data and file structure We tested whether warm spells in winter affect the baseline and stress-induced cortisol level, and leukocyte relative telomere length in two winter phenotypes of Siberian hamster *Phodopus sungorus*, responding and non-responding to short photoperiod. ### Files and variables #### File: cortisol.xlsx **Description:** Cortisol concentration were measured in blood using liquid chromatography/tandem mass spectrometry (LC-MS-MS). Blood was drawn after summer-like acclimation and after 16 weeks of winter-like acclimation. We measured animals acclimated to stable winter-like conditions (ST; 8L:16D, 7°C), or unstable winter-like conditions (NST; 8L:16D, ambient temperature varying between 7°C and 20°C in an unpredictable cycle). Animals presentd different winter phenotype: repsonding (R) and nonresponding (NR) to shortening photoperiod. We measured animals in summer and winter and we measured both: baseline cortisol (BASE) and stress-induced cortisol (STRESS) in females (F) and males (M). Cortisol was calculated to ng/ml (CORT). Variables * ID (identification number) - winter conditions (ST: stable winter-like conditions; NST: unstable winter-like conditions). * sex (M - male; F - female) - phenotype (R - responding; NR - nonresponding) * SEASON (summer and winter) - stress (BASE - baseline cortisol; STRESS - stress-induced cortisol) * body mass (in grams) - CORT-cortisol concentrtion (in ng/mL) File: RTL_Leuco.xlsx **Description:** Relative telomere length (RTL) was measured with the quantitative polymerase chain reaction (qPCR) approach. Blood was drawn after summer-like acclimation and after 22 weeks of winter-like acclimation. We measured animals acclimated to stable winter-like conditions (ST; 8L:16D, 7°C), or unstable winter-like conditions (NST; 8L:16D, *T*a varying between 7°C and 20°C in an unpredictable cycle). Animals presentd different winter phenotype: repsonding (R) and nonresponding (NR) to shortening photoperiod. We measured animals in summer and winter and we measured both: baseline cortisol (BASE) and stress-induced cortisol (STRESS) in females (F) and males (M). Teleomers were measured in leucocytes therefore we calculated also the number of lymphocytes, neutrophils, basophils, monocytes, eosinophils i both season: winter and summer. Variables * ID (identification number) - winter conditions (ST: stable winter-like conditions; NST: unstable winter-like conditions). * phenotype (R - responding; NR - nonresponding) - sex (M - male; F - female) * body mass summer (in grams) - body mass winter (in grams) * number of torpor episodes until 16 week of winter acclimation - number of torpor episodes until 22 week of winter acclimation * RTL summer (relative telomere length in summer) - RTL winter (relative telomere length in winter) * Summer-neutrophils (proportion of neutrophils in summer) - Summer-lymphocytes (proportion of lymphocytes in summer) * Summer-eosinophils (proportion of eosinophils in summer) - Summer-monocytes (proportion of monocytes in summer) * Summer-basophils (proportion of basophils in summer) - Summer-N/L ratio (neutrophils to lymphocytes ratio in summer) * Winter-neutrophils (proportion of neutrophils in winter) - Winter-lymphocytes (proportion of lymphocytes in winter) * Winter-eosinophils (proportion of eosinophils in winter) - Winter-monocytes (proportion of monocytes in winter) * Winter-basophils (proportion of basophils in winter) - Winter-N/L ratio (neutrophils to lymphocytes ratio in winter) **File: testosterone.xslx** **Description:** Testosterone concentration were measured only in male Siberian hasmters, in blood using liquid chromatography/tandem mass spectrometry (LC-MS-MS). Blood was drawn after summer-like acclimation and after 16 weeks of winter-like acclimation. We measured animals acclimated to stable winter-like conditions (ST; 8L:16D, 7°C), or unstable winter-like conditions (NST; 8L:16D, *T*a varying between 7°C and 20°C in an unpredictable cycle). Animals presented different winter phenotype: repsonding (R) and nonresponding (NR) to shortening photoperiod. We measured animals in summer and winter. Testosterone was calculated to ng/ml (test). Variables * ID (identification number) - winter conditions (ST: stable winter-like conditions; NST: unstable winter-like conditions). * phenotype (R - responding; NR - nonresponding) - SEASON (summer and winter) * testosterone concentration (in ng/mL) ## Code/software Microsoft Office Excel can be used to view the files