SUMMARYHypoxia-inducible factor (HIF)-1ais essential following a myocardial infarction (MI), and diabetic patients havepoorer prognosis post-MI. Could HIF-1aactivation be abnormal in the diabetic heart, and could metabolism becausing this? Diabetic hearts had decreased HIF-1aprotein following ischemia, and insulin-resistant cardio-myocytes had decreased HIF-1a-mediated signaling and adaptation to hypoxia. This was due to elevated fattyacid (FA) metabolism preventing HIF-1aprotein stabilization. FAs exerted their effect by decreasing succinateconcentrations, a HIF-1aactivator that inhibits the regulatory HIF hydroxylase enzymes. In vivo and in vitropharmacological HIF hydroxylase inhibition restored HIF-1aaccumulation and improved post-ischemic func-tional recovery in diabetes.