Abstract
Profiles of total and free insulins in diabetic patients' plasma with insulin antibodies were studied before and after subcutaneous insulin injections. We have developed an easy acid-ethanol extraction method for the determination of bound insulin. A strong correlation existed between the total insulin level determined by the acid-PEG method (Nakagawa et al. 1973) and our acid-ethanol method; however, the latter gave much less coprecipitation and better recovery (99.2%). Small decreases in total and free insulin levels were found during sample storage prior to assay.
Total and free insulins were measured in 22 diabetics with insulin antibodies before and 2 hours after subcutaneous insulin injections. The increment in free insulin revealed no significant correlation with antibody level. The increment in bound insulin, however, was greater in patients with high antibody levels, suggesting a lower metabolic rate of bound insulin.
