New approaches to therapy and diagnosis of diabetes

Recent progress within the field of molecular biology has resulted in the development of a new technology known as 'recombinant DNA'. This technology deals with a number of biochemical techniques for handling DNA which include: (1) cutting DNA at specific sites, (2) inserting DNA into bacteria or mammalian cells so that the cell will replicate the DNA and (3) manipulation of cloned DNA so that the host cell makes the protein for which the DNA codes [1-3]. Already a number of hormones including somatostatin, human growth hormone and human insulin [4] have been produced by these new methods. However, there are certain criteria which should be considered before new sources of hormones are generally accepted for treatment of human diseases. We shall review some of the problems which may arise in the case of insulin, by comparing the chemical and immunological properties of insulin from various sources. Recombinant DNA methods have, in addition, made it possible to study islet cell structure and function at the gene level. These studies include analysis of gene structure and of how they are transcribed and translated. Structural analyses which seem to be significant in the differential diagnosis of diabetes will be reviewed.