Effect of Acute Muscular Exercise on Serum Immunoreactive Insulin Concentration

Abstract
The change in circulating levels of immunoreactive insulin (IRI) was studied in a group of six normal, three obese, and eight obese diabetic subjects undergoing the acute exercise of stair climbing. Bloods were sampled immediately before and after the exercise period. Serum IRI concentration decreased in ten subjects and did not increase in the remainder of the subjects. The data suggest an exercise metabolite rather than increased insulin secretion accounts for the enhanced glucose assimilation produced by muscular activity.