The isolation of insulin and the demonstration of its efficacy in the management of the diabetic state won the Nobel Prize in Medicine for Drs. Banting and McLeod in 1923. Despite the brilliance of this discovery and this most dramatic introduction of insulin into the practice of medicine, it gradually became evident that diabetes mellitus is not a simple matter of insulin deficiency. Now, almost 4 decades later, we continue to be mystified by the physiology of this hormone and how it relates to human disease.
Insulin Assay Methods
Much of the confusion in this field is directly attributable to the difficulties that have been encountered in developing reliable methodology for the determination of the minute quantities of insulin present in blood. According to the best available estimates, plasma from normal fasting human subjects contains only about 100-1,000 microunits (units × 10−6) of insulin per milliliter. The only techniques