Insulin deficiency in non-insulin-dependent diabetes

Lancet. 1989 Feb 11;1(8633):293-5. doi: 10.1016/s0140-6736(89)91306-8.


A highly specific two-site immunoradiometric assay for insulin was used to measure the plasma insulin response to 75 g glucose administered orally to 49 patients with non-insulin-dependent diabetes (NIDDM). The plasma insulin concentration 30 min after glucose ingestion was lower in the diabetic patients than in matched controls for both non-obese (11-83 pmol/l vs 136-297 pmol/l, p less than 0.01) and obese subjects (23-119 pmol/l vs 137-378 pmol/l, p less than 0.01). By means of another two-site immunoradiometric assay, the basal intact proinsulin level was found to be higher in the NIDDM patients than in the controls for both non-obese (7.1 [SEM 1.2] pmol/l vs 2.4 [0.4] pmol/l, p less than 0.01) and obese subjects (14.4 [2.2] pmol/l vs 5.9 [1.9] pmol/l, p less than 0.01). The basal level of 32-33 split proinsulin was also raised in NIDDM. Previous failure to show clear separation between normal and NIDDM insulin responses was probably due to the high concentrations of proinsulin-like molecules in the plasma of NIDDM patients. These substances cross-react as insulin in most, if not all, insulin radioimmunoassays but have very little biological insulin-like activity. It is therefore now possible and necessary to designate most NIDDM patients as insulin deficient.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Diabetes Mellitus, Type 2 / blood*
  • Evaluation Studies as Topic
  • Glucose Tolerance Test
  • Humans
  • Insulin / deficiency*
  • Insulin Resistance
  • Middle Aged
  • Obesity / blood
  • Proinsulin / blood
  • Radioimmunoassay
  • Time Factors


  • Insulin
  • Proinsulin