Chapter 7 **Thyrotropin-Releasing Hormone (TRH) a Small Molecule in Pancreas Promotes Insulin Producing Cell Proliferation 155** John Z.Q . Luo, Souriya Vang, Zhao Ting, Ivor Jackson and LuGuang Luo

Preface

age group.

people with diabetes remain undiagnosed.

past decades, namely: the Na+

molecular mechanisms of diabetes and insulin resistance.

specificities, kinetic properties and tissue expression profiles.

At least one in ten people today are destined, on current trends, to develop diabetes at some point during their lifetime. The total number of individuals with diabetes worldwide is scheduled to double in a generation. WHO has defined type 2 diabetes mellitus, a progres‐ sive worldwide epidemic. The statistics are alarming: 30 million people were diagnosed with diabetes worldwide in 1985. By 1995, the number had risen to 135 million. It has been estimated that by 2010, 220 million people worldwide will be affected by the disease, and there will be some 300 million by the year 2015 as predicted by WHO. According to another statistics, the prevalence of all forms of diabetes is estimated to be 2–3% of the world's popu‐ lation, with the number of diabetic patients increasing by 4–5% per annum. Moreover, many

Type 1 diabetes is observed in approximately 5–10% of patients with diabetes mellitus. The incidence of type 1 diabetes is projected to increase 40% between 1997 and 2010. The studies suggest an annual global increase of 3–4% with the highest increase expected in the 0–4 year

The progress in molecular biology, genetics, epidemiology and in clinical applications not‐ withstanding, much more needs to be done. It will be of great importance to identify the

Most tissues and organs, such as the brain, need glucose constantly, as an important source of energy. The low blood concentrations of glucose can cause seizures, loss of consciousness, and death. On the other hand, long lasting elevation of blood glucose concentrations can result in blindness, renal failure, cardiac and peripheral vascular disease, and neuropathy. Therefore, blood glucose concentrations need to be maintained within narrow limits. The process of maintaining blood glucose at a steady-state level is called glucose homeostasis. This is accomplished by the finely hormone regulation of peripheral glucose uptake (glucose utilization), hepatic glucose production and glucose uptake during carbohydrates ingestion. Glucose is obtained directly from the diet and by the synthesis from other substances in or‐ gans such as liver. Glucose derived from the diet is transferred from the lumen of small in‐ testine, and both dietary glucose and glucose synthesized within the body have to be transported from the circulation into target cell. Glucose cannot penetrate the lipid bilayer, and specific carrier proteins are required to its diffusion. These transporters comprise two structurally and functionally distinct groups, whose members have been identified over the

dependent sugar transporters (GLUT). These various transporters exhibit different substrate


