Infusion of synthetic human C-peptide does not affect plasma glucose, serum insulin, or plasma glucagon in healthy subjects

Abstract We studied six healthy male subjects to determine whether a four-hour infusion of synthetic human C-peptide sufficient to achieve mean (±SD) peripheral plasma concentrations of 1.3 ± 0.7 pmol/mL affected plasma glucose, serum insulin, or plasma glucagon. Subjects were studied in a fasting state and following an oral glucose load during four-hour 0.9% NaCl (control) and C-peptide (mean dose: 70 nmol) infusions. No differences were observed between saline and C-peptide infusions for mean values of fasting plasma glucose (94 ± 6 v 87 ± 5 mg/dL), serum insulin (3 ± 1 v 2 ± 1 μ U/mL), or plasma glucagon (124 ± 65 v 112 ± 70 pg/dL). Following oral glucose ingestion no differences were detected between saline and C-peptide infusions for mean peak values of plasma glucose (168 ± 18 v 168 ± 31) and serum insulin (59 ± 6 v 57 ± 21) or mean nadir values of plasma glucagon (80 ± 73 v 75 ± 70). There was a slight delay in the insulin rise following oral glucose on the C-peptide infusion day, but differences between mean values for individual sampling times were not statistically significantly different.