BETA-CELL BEHAVIOR DURING THE PREDIABETIC STAGE .1. BETA-CELL PATHOPHYSIOLOGY

beta-cell function in non-insulin dependent diabetes mellitus (NIDDM) or type II diabetes, in particular during the prediabetic stage, has b een more extensively investigated than in insulin-dependent diabetes m ellitus (IDDM) or type I diabetes. Recently, however, the existence of a beta-cell dysfunction, early during the prediabetic stage of IDDM, and its possible contribution to the amplification of the autoimmune r eaction have been underlined. Here, in a first of two parts, an attemp t is made to review the various ways normal beta cells cope with incre ased demands an their resources in different models of hyperglycaemia in order to better delineate and compare the mechanisms implicating be ta cells in the pathogenesis of both types of diabetes.