HIF-1α in adenosine kinase (AK) repression in vivo. AK-mRNA levels were examined in mucosal scrapings from the colon (A) or lung tissue (B) derived from conditional Hif-1α–deficient mice targeted toward the intestinal epithelium (Hif-1α^−/−, , wild-type controls [WT], ■) subjected to either normoxia or normobaric hypoxia (8% oxygen) for 4 hours. *P < .01 indicates difference between normoxia and hypoxia; #P < .001 indicates difference between WT and Hif-1α^−/−. Results are derived from 5 animals per group.