The effect of pinealectomy on non-shivering thermogenesis and hibernation of the wyoming ground squirrel, Spermophilus elegans

1. 1.|Pineal gland removal (PX) performed on Wyoming ground squirrels ( Spermophilus elegans) during the summer significantly lowered their non-shivering thermogenic (NST) response and impaired their ability to hibernate the subsequent winter. 2. 2.|This impairment was not observed in previous studies on squirrels PX'd later in the season. A period of responsiveness for involvement of the pineal gland in NST and hibernation is, therefore, presented. 3. 3.|Environmental signals translated by the pineal gland which influence the NST response do not appear to be thermal cues but are more than likely photic information. 4. 4.|Reduced impairment of the NST response was observed in squirrels PX'd for 3 yr compared to the 1st PX'd group. However, this may simply be a result of the 3-yr PX'd group being tested later in the hibernation cycle.