ABSTRACT
Diabetes mellitus is a highly prevalent metabolic disease, in which the pancreas does not produce enough insulin to meet its need or the body does not effectively use the insulin it produces. This leads to the elevated levels of blood glucose (hyperglycemia), which can induce the spillage of glucose into the urine (Hayashi and Ito 2002; Hayashi et al. 2006). Diabetes mellitus is classied into two major types as type 1 and type 2. Type 1 is known as insulin-dependent or childhood-onset diabetes mellitus (IDDM) and is characterized by the destruction of the insulin-producing β cells in the pancreatic islets of Langerhans, which leads to loss of insulin secretion. Type 2 is formerly called noninsulin-dependent or adult-onset diabetes mellitus (NIDDM), which is further subdivided into obese or lean (nonobese) type, and is caused by the body’s ineffective use of insulin. It is often caused from excess body weight and physical inactivity and is dened by a raised fasting or postchallenge blood glucose level (Do et al. 2008). Diabetes in clinical diagnosis usually accompanies the symptom of hypercholesterolemia with hyperglycemia, which can damage blood vessels, referred to as microvascular disease, and increases the risk of heart attack, stroke, and kidney failure (Dieterle et al. 2006). Therefore, hyperglycemia and hypercholesterolemia are well-known major cardiovascular risk factors in type 2 diabetes. The hyperglycemic and hypercholesterolemic activities in diabetic animal models have been adopted for antidiabetic study. Streptozotocin (STZ)- induced diabetes has been well recognized in animal studies for type 1 and type 2 diabetes. STZ is particularly toxic to the insulin-producing beta cells of the pancreas in mammals.
