Ingestion of a mixed meal does not affect the metabolic clearance rate of biosynthetic human C-peptide.
The validity of C-peptide as a peripheral marker of insulin secretion during different physiological conditions depends on the demonstration that C-peptide clearance is constant under these circumstances. Recently biosynthetic human C-peptide, identical in structure to pancreatic human C-peptide, became available for use in human subjects. The present study was undertaken to determine if the metabolic clearance of C-peptide was altered by ingestion of a mixed meal. Eight insulin-dependent diabetic patients received constant iv infusions of biosynthetic human C-peptide which raised the plasma C-peptide concentration to a level of 3.8 +/- 0.2 (+/- SEM) pmol/ml. The MCR of C-peptide was 4.5 +/- 0.3 ml/kg X min. After steady state levels of C-peptide had been reached, each patient consumed a 530 calorie mixed meal. The plasma glucose concentration increased from a baseline value of 104.5 +/- 4.8 mg/dl to a 336 +/- 10 mg/dl 150 min later. This change in plasma glucose was not associated with a significant alteration in the plasma C-peptide concentration and the MCR of the infused C-peptide was not affected by meal ingestion (4.5 +/- 0.3 vs. 4.3 +/- 0.3 ml/kg X min). These results therefore support the validity of using C-peptide as a marker for changes in insulin secretion after mixed meals.
D000328:Adult; D001786:Blood Glucose / Q000378:metabolism; D002096:C-Peptide / Q000097:blood*; D003922:Diabetes Mellitus, Type 1 / Q000097:blood*; D004032:Diet; D005260:Female; D006801:Humans; D008297:Male; D008657:Metabolic Clearance Rate; D011994:Recombinant Proteins / Q000097:blood*
D001786:Blood Glucose; D002096:C-Peptide; D011994:Recombinant Proteins