PTGS2 and diabetes mellitus: In this regard, mice treated with a high dose of streptozotocin (STZ, a chemically-induced diabetes model), displayed an increase in Ptgs2/Cox2 expression in whole pancreas and isolated islets, but strikingly, these authors found that constitutive Ptgs2/Cox2 knock out animals displayed significantly a higher incidence of hyperglycaemia, both after a single high dose and after several low doses of STZ 46.