These data were collected from arctic ground squirrels (Urocitellus parryii) between Summer 2016 and Spring 2019 on a collaborative NSF-funded project examining the neuroendocrine regulation of the transition between hibernation and reproduction. The three experiments consist of (1) a repeated cross-sectional study conducted in both males and females hibernating in constant darkness and constant temperature (2) an extreme mid-winter warming study conducted in males only and (3) an end of hibernation warming study conducted in both males and females under biologically relevant hibernaculum temperatures.  These datasets quantify changes in retrograde thyroid hormone signaling between the pars tuberalis and hypothalamus; ultrastructural changes in pars tuberalis thyrotrophs, anterior pituitary gonadotrophs, and tanycytic endfeet at the median eminence; hypothalamic changes in the expression of nestin and Vimentin, and changes in reproductive parameters across the hypothalamic-pituitary-gonadal axis. 

Missing data are denoted with "NA". Data are organized by experiment number (1, 2, 3) and by type (csv, image).