Sexual differences at anoxia resistance in Trachemys scripta

Abstract

To maintain and modulate homeostasis and vital functions, vertebrates depend on oxygen. Despite that, freshwater turtles are able to tolerate oxygen depletion conditions, and anoxia, by lowering their metabolic rate drastically. In the environment, these anoxic periods, which are dependent on temperature, can endure up to forty days. The cellular metabolism of turtles changes from aerobic oxidative fosforilation to anaerobic glycolysis, a process which rise significantly the lactate concentration. During the depletion of oxygen in water, plasma pH decrease, rising the monoamine concentration (especially noradrenaline) and resulting in the elevation of muscular glycogenolysis and blood hyperglycemia. Despite the number of studies regarding the genetic, metabolic, physiological, evolutionary, and behavioral adaptations in freshwater turtles in anoxia, nothing has been explored in the sexual differences of these adaptations. This project aims to evaluate differences linked to sex hormones in the anoxia resistance in male and female adults of Trachemys script. That will be addressed by analyzing lactate and glycogen metabolism in the plasma, arterial pH, temperature, HIF-1 expression, and the number of catecholamines in the brain of males and females after 12 hours of normoxia, hypoxia, and anoxia exposure compared to the different phases of the reproductive cycle in these animals.(AU)