Abstract
A 52-year-old nurse came to our clinic because of hypoglycemic attacks. At 45 years of age she had been diagnosed as having bronchial asthma, and was subsequently treated with subcutaneous injections of insulin and aurothioglucose for eight months.
About two years after the injections ended, she begun to experience episodic hyoglycemic attacks. The blood glucose levels during the attacks ranged from 30 to 50mg/dl. A 75g oral glucose tolerance test revealed border-line conditions. Echographic and radiological examinations revealed nothing remarkable. The levels of immunoreactive insulin (IRI) and C-peptide immunoreactivity (CPR) extracted from the serum by the acid-ethanol method were enormously elevated, as was also the percentage of 1251-insulin binding. The elevated CPR was mainly due to increased proinsulin, which was confirmed by gel-filtration. Reverse-flow high-speed liquid chromatography revealed that the extracted insulin was normal human insulin. Bw62, Cw4, and DR4 were found in the typing of HLA. These results indicated that the hypoglycemia might be explained by the antibodies binding secreted insulin.
Corticosteroid treatment for three months reduced the frequency and severity of the hypoglycemic attacks concomitantly with decrease in the serum levels of insulin and proinsulin, and in the percentage of 125I-insulin binding of the serum.
