Metformin Works in Different Way than Previously Thought (image) University of Pennsylvania School of Medicine Share Print E-Mail Caption Proposed model: Metformin enters the cell and acts on the mitochondria, causing increased AMP. Elevated cellular AMP levels inhibit membrane bound adenylyl cyclase, causing a reduction in cellular cAMP levels and decreased PKA activation and target phosphorylation. Credit Morris Birnbaum, M.D., Ph.D., Perelman School of Medicine, University of Pennsylvania; Nature Usage Restrictions None Share Print E-Mail Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.