Altered C-peptide/insulin molar ratios and glucose turnover rates after stimulation in nondiabetic offsprings of type II diabetic patients.
We evaluated the serum glucose/insulin/C-peptide dynamics and C-peptide/insulin molar ratios during sequential standard meal and intravenous (IV) glucagon testing for 240 minutes in eight genetically predisposed but nondiabetic female offsprings of type II diabetic patients and seven weight-matched, normal female controls. Glucose turnover rates and metabolic clearance rates of glucose (MCRG) were also determined isotopically by the D-[3-3H]glucose infusion technique. All the subjects had normal fasting serum glucose and glycosylated hemoglobin (HbA1) values. After meal ingestion, mean serum glucose concentrations were not different except for 120 to 180 minute values, which were significantly higher in the offsprings v controls. After intravenous glucagon infusion, percent maximum increments of glucose were no different. Mean basal immunoreactive insulin (IRI) levels were significantly (P less than 0.02) higher in the nondiabetic offsprings v controls. Following meal ingestion, mean IRI rose to a peak at 40 minutes in both groups, but values were significantly (P less than 0.001) higher in the offsprings v controls. After glucagon administration, the percent maximum increment was significantly (P less than 0.05) lower in the offsprings v controls. Despite exaggerated IRI levels in the offsprings, the mean fasting and stimulated C-peptide levels were identical in both groups throughout the study period. Basal and stimulated C-peptide/IRI molar ratios were quantitatively lower but qualitatively no different in the nondiabetic offsprings v controls throughout the study period. Mean basal hepatic glucose output (HGO) was higher but not statistically different in the offsprings compared with the controls (2.10 +/- 0.28 v 1.65 +/- 0.15 mg/kg X min).(ABSTRACT TRUNCATED AT 250 WORDS)
D000293:Adolescent; D000328:Adult; D001786:Blood Glucose / Q000378:metabolism*; D002096:C-Peptide / Q000097:blood*; D003924:Diabetes Mellitus, Type 2 / Q000235:genetics*; D005934:Glucagon; D006801:Humans; D007328:Insulin / Q000097:blood*; D008099:Liver / Q000378:metabolism; D008657:Metabolic Clearance Rate; D013997:Time Factors
D001786:Blood Glucose; D002096:C-Peptide; D007328:Insulin; D005934:Glucagon