MPO and diabetes mellitus: To ensure that the inability of the drugs to affect diabetes incidence was not due to inefficacious enzyme inhibition in vivo, potentially reflecting an inefficactious concentration inside the spleen and/or pancreas, we measured NE and MPO activity in pancreas and spleen homogenates in mice fed with control or drug-manufactured (AZD9668+AZD5904 together) diets for 14 days.