Relationship of Glycosylated Haemoglobin to C-Peptide Secretory Status and Antibody Binding of Insulin in Insulin-Dependent Diabetes

Summary

Diabetic control, assessed by measuring the concentration in venous blood of total glycosylated haemoglobin (HbA1), endogenous insulin secretion, as estimated by the C-peptide response (Δ-P) to intravenous glucagon, and serum beef insulin antibody binding were measured in 50 juvenile onset insulin dependent diabetics (IDDM) receiving a single daily injection of soluble and protamine zinc insulin. The ΔC-P correlated inversely with duration of diabetes (τ = -0.27, p < 0.01) and daily insulin requirement (τ = -0.22, p < 0.05) in the 50 IDDM studied of whom 28 exhibited a measurable ΔC-P. In C-peptide nonresponders, but not in the C-peptide responders, an inverse regression (τ = 2.19, p < 0.05) was observed between beef insulin antibody binding and HbA1. In the 25 IDDM having the lowest insulin antibody binding, an inverse correlation (τ = 0.36, p < 0.02) was observed between ΔCP and HbA1, which was not found (τ = 0.05) in the remaining 25 IDDM who had the highest insulin antibody binding.

These findings suggest that, in the absence of endogenous insulin secretion, diabetic control in IDDM receiving a single daily injection of conventional beef insulin is better in patients with high beef insulin antibody binding. Conversely, in patients with low beef insulin antibody binding, diabetic control appears to be better in those with persisting endogenous insulin secretion.

Key-Words:

Glycosylated Haemoglobin - C-Peptide Secretion - Insulin Antibody Binding - Insulin Enzyme - Insulin Dependent Diabetes