Fig. 1.

Depletion of circulating lymphocytes during torpor is temperature dependent and unaffected by splenectomy. (A) Normal blood lymphocyte count of summer-euthermic Syrian hamster. (B) Body temperature-dependent decrease in blood lymphocytes upon entrance into torpor and to a similar extent in forced hypothermia in nonhibernating animals. (C) Blood lymphocyte counts are restored rapidly during rewarming from torpor and from forced hypothermia. (D) Circulating lymphocyte number is reduced during daily torpor in the Djungarian hamster. (E) Splenectomy before hibernation does not inhibit induction of lymphopenia in torpor. (F) Splenectomy during torpor does not preclude restoration of blood lymphocyte count during the subsequent arousal. Bars represent mean ± SEM of four to eight animals per group. Groups were compared using student's t-test or one-way ANOVA and post hoc least significant difference. *P < 0.05.