Repeatability of C-peptide response in glucagon stimulation test

Area of Science:

• Endocrinology
• Metabolic Disorders
• Geriatric Medicine

Background:

• C-peptide levels reflect endogenous insulin production.
• Assessing C-peptide response to stimuli like glucagon is crucial for evaluating pancreatic beta-cell function.
• Understanding the repeatability of these measurements is essential for reliable clinical interpretation, especially in aging populations.

Purpose of the Study:

• To evaluate the repeatability of plasma C-peptide responses to intravenous glucagon administration.
• To assess C-peptide response reliability in both elderly non-diabetic subjects and elderly individuals with non-insulin-dependent diabetes mellitus.

Main Methods:

• Repeated measurements of plasma C-peptide levels before and after intravenous glucagon (1 mg) administration.
• Four test sessions were conducted on 10 non-diabetic and 20 non-insulin-dependent diabetic elderly subjects.
• Analysis included C-peptide levels and C-peptide/glucose ratios.

Main Results:

• No significant differences were observed in plasma C-peptide levels or C-peptide/glucose ratios across the four repeated measurements.
• Repeatability was consistent in both the non-diabetic and diabetic elderly subject groups.
• The C-peptide response to glucagon demonstrated high test-retest reliability.

Conclusions:

• The C-peptide response to glucagon is highly repeatable in elderly non-diabetic individuals.
• The C-peptide response to glucagon is also highly repeatable in elderly patients with non-insulin-dependent diabetes mellitus.
• These findings confirm the reliability of glucagon-stimulated C-peptide testing for assessing beta-cell function in older adults.