Discrimination of type I from insulin-treated type II diabetic patients by C-peptide measurement

Abstract

Residual B-cell function was assessed in 61 type I and 17 type II insulin-treated diabetics by measuring plasma C-peptide concentration before and after i.v. injection of 1 mg glucagon to evaluate a possible difference in response to the test in the two groups. Fasting and post-stimulatory C-peptide levels were significantly higher in type II diabetics than in type I (0.45 +/- 0.25 vs 0.12 +/- 0.10 nmol/l for basal IRCP, 0.39 +/- 0.19 vs 0.06 +/- 0.11 nmol/l for delta IRCP, p less than 0.0001), but there was some overlap in individual values. Twenty-one percent of type I and 29% of type II diabetics had values in the overlap area. These percentages were reduced to 6% and 12%, respectively when only long-term (duration of diabetes more than five years) type I diabetics were considered. These data indicate that a glucagon test is useful to discriminate most type I diabetics from insulin-treated type II diabetics.

Low O2-induced ATP release from erythrocytes of humans with type 2 diabetes is restored by physiological ratios of C-peptide and insulin

“…retain modest beta-cell activity, allowing for the production of low levels of C-peptide (9,10,20). In a study analyzing patient tertiles based on C-peptide levels, the incidence of retinopathy, nephropathy, and neuropathy decreased from the first (Cpeptide Յ 0.47 nM) to the third tertile (C-peptide Ն 0.80 nM) (7).…”

“…In a study analyzing patient tertiles based on C-peptide levels, the incidence of retinopathy, nephropathy, and neuropathy decreased from the first (Cpeptide Յ 0.47 nM) to the third tertile (C-peptide Ն 0.80 nM) (7). In humans with type 2 diabetes, several reports suggest that a basal level of C-peptide of ϳ0.4 nM is often present, with minimal increases occurring after meals due to some residual beta-cell activity (9,10,20). Here, we report that in the presence of 1 nM insulin-a concentration of insulin that may be present in insulin-treated humans with type 2 diabetes-0.4 nM C-peptide is insufficient to restore low O 2 -induced ATP release from erythrocytes of humans with type 2 diabetes (Fig.…”

Relationship between the prevalence of anti-glutamic acid decarboxylase autoantibodies and duration of type 1 diabetes mellitus in Brazilian patients

“…Individuals that had stopped insulin therapy for more than two weeks since the diagnosis of diabetes and had not developed DKA were also excluded. Random C peptide was measured in all participants and was used as an exclusion criterion if >1.5 ng/ml in patients with the duration of disease ≥3 years, which makes a diagnosis of T1D improbable (9,10).…”

Understanding Pancreatic Secretion in Type 1 Diabetes

“…Several studies indicate that the loss of functional capacity usually occurs within three to five years. Most patients with long duration of disease do not present clinical evidence of preservation of cells (9)(10)(11). However, the conservation of some residual secretion, even insufficient to cure or prevent T1DM from using insulin, has been associated with a better prognosis regarding glycemic control, lower rates of hypoglycemia, diabetic retinopathy and nephropathy (12).…”