CYP19A1 and Insulin resistance: Aromatase KO (ArKO) mice display increased adiposity, glucose intolerance and insulin resistance in both sexes (302); in male ArKO mice, increased insulin resistance is primarily due to increased hepatic gluconeogenesis through the induction of G6Pase (glucose 6-phosphatase) and Pepck (phosphoenolpyruvate carboxykinase) expression (299).