Insulin: chemistry, synthesis and secretion

Abstract

Any attempt at understanding the aetiology and pathophysiology of diabetes, particularly type II or non-insulin-dependent diabetes, and at evaluating therapeutic strategies to treat the disease must start with a knowledge of the structure of insulin and its related chemistry. Significant consideration must be given to how insulin is synthesized in, and secreted from, the pancreas. The latter topics are of less relative importance with insulin-dependent or type I diabetes since the destruction of the β-cell is the pathological defect in this condition. In type II diabetes, the ability of the pancreas to synthesize and secrete insulin is maintained. In fact, the ability to secrete insulin in response to such secretagogues as arginine is the same as in controls. However, the response to glucose is considerably decreased. These observations emphasise the need for consideration of the above topics in therapeutic evaluation.