The effect of acute hyperglycemia on the plasma C-peptide response to intravenous glucagon or to a mixed meal in insulin-dependent diabetes mellitus.
The dose-response relationships between prestimulatory blood glucose concentration and the plasma C-peptide responses to stimulation with 1 mg of glucagon iv or a standard mixed meal were studied in 8 C-peptide positive patients with insulin-dependent diabetes mellitus. Hyperglycemia was maintained for 90 min before stimulation using a hyperglycemic clamp technique. Each test was performed at the steady state blood glucose levels approximately 5, approximately 12, and approximately 20 mmol/l. The glucose potentiation of the incremental plasma C-peptide area under the curve at the two levels of hyperglycemia in percent of the area at normoglycemia (median and range) was 343% (53-1053) (p less than 0.05) and 341% (267-1027) (p less than 0.05) after glucagon and 140% (76-227) (NS) and 251% (95-1700) (p less than 0.05) after the meal. The corresponding relative glucose potentiation of plasma C-peptide 6 min after stimulation with glucagon was 124% (100-427) (p less than 0.02) and 144% (100-209) (p less than 0.05). There was no significant difference in the degree of glucose potentiation at approximately 12 or approximately 20 mmol/l. Furthermore, there was no significant difference in the degree of glucose potentiation of the different estimated values of B-cell function. In conclusion, the plasma C-peptide responses to iv glucagon or to a standard test meal were markedly potentiated by acute hyperglycemia in insulin-dependent diabetes mellitus. No further potentiation was, however, obtained when the prestimulatory blood glucose concentration was raised above 12 mmol/l.(ABSTRACT TRUNCATED AT 250 WORDS)
Gjessing
H J
HJ
Division of Endocrinology and Metabolism, University Clinic of Internal Medicine, Arhus Amtssygehus, Denmark.
Reinholdt
B
B
Faber
O K
OK
Pedersen
O
O
D000208:Acute Disease; D000293:Adolescent; D000328:Adult; D001786:Blood Glucose / Q000378:metabolism; D002096:C-Peptide / Q000097:blood*; D003922:Diabetes Mellitus, Type 1 / Q000097:blood* / Q000503:physiopathology; D004305:Dose-Response Relationship, Drug; D005260:Female; D005502:Food; D005934:Glucagon / Q000032:analysis / Q000494:pharmacology*; D006801:Humans; D006943:Hyperglycemia / Q000097:blood* / Q000503:physiopathology; D007275:Injections, Intravenous; D007515:Islets of Langerhans / Q000187:drug effects / Q000378:metabolism / Q000502:physiology; D008297:Male
D001786:Blood Glucose; D002096:C-Peptide; D005934:Glucagon