Physiological and behavioral correlates of HIF-1 alpha protein levels in the Gulf killifish, Fundulus grandis

Although the hypoxia-inducible transcription factor (HIF) orchestrates molecular responses to low oxygen, the amount of HIF-1α protein expressed during hypoxia varies among species, individuals, and tissues. This study measured HIF-1α protein levels along with several physiological and behavioral variables in the estuarine fish Fundulus grandis under normoxia (\u3e 7 mg l-1 dissolved oxygen) and hypoxia (1 mg l-1 dissolved oxygen). Fish under hypoxic conditions had higher tissue levels of HIF-1α, hematocrit, blood glucose, blood lactate, frequency of aquatic surface respiration (ASR), and lower activity than normoxic controls. Under hypoxia, HIF-1α abundance in gill was positively correlated with body mass, HIF-1α abundance in liver was positively correlated with blood lactate, and HIF-1α abundance in brain was negatively correlated with time the fish was quiescent. Therefore, this work reveals that heterogeneity in HIF-1ɑ protein in tissues of fish is related to select physiological and behavioral variables under hypoxia