C-Peptide responses to glucose load in maturity-onset diabetes of the young (MODY).

Pancreatic beta cell responses were measured in obese and nonobese maturity-onset diabetes of the young (MODY) patients by estimating serum immunoreactive insulin (IRI) and C-peptide (CP) during oral glucose tolerance testing (OGTT). The serum CP responses were generally low in MODY patients and more pronounced in obese patients. The IRI responses were heterogenous; some patients had normal and others low responses. It was observed that in several patients there was a relatively higher IRI concentration in comparison with the CP values, as indicated by low CP and normal IRI values. This is suggestive of altered metabolic fates of insulin and CP in the MODY patients.