title: Reproducibility of beta-cell function estimates in non-insulin-dependent diabetes mellitus.
abstract: We evaluated the reproducibility of different estimates of endogenous insulin secretion in 30 patients with non-insulin-dependent diabetes mellitus (NIDDM). Fasting blood glucose concentration was similar on the 2 days of study. The coefficients of variation of fasting plasma C-peptide, plasma C-peptide 6 min after the injection of 1 mg i.v. glucagon, and the increment in plasma C-peptide after glucagon were 16.0, 14.8 and 24.1%, respectively. The coefficients of variation of the corresponding plasma insulin values were 19.2, 24.8, and 34.8%, respectively. The coefficient of variation of 24-h urinary C-peptide excretion was 22.1%. Because fasting plasma C-peptide correlated closely with plasma C-peptide 6 min after glucagon (test 1: r = .70, P less than .01; test 2: r = .76, P less than .01), it seems that these two values can be used equally well as assessment of beta-cell function in NIDDM. In conclusion, fasting plasma insulin, fasting plasma C-peptide, and plasma C-peptide 6 min after glucagon stimulation showed a similar and acceptable degree of reproducibility. Plasma insulin 6 min after glucagon and increments in plasma insulin and C-peptide, as well as urinary C-peptide, seem to be less reproducible.
authors.forename: H J
authors.initials: HJ
authors.lastname: Gjessing
authors.forename: E M
authors.initials: EM
authors.lastname: Damsgaard
authors.forename: L E
authors.initials: LE
authors.lastname: Matzen
authors.forename: A
authors.initials: A
authors.lastname: Frøland
authors.forename: O K
authors.initials: OK
authors.lastname: Faber
mesh_terms: D000368:Aged; D002096:C-Peptide / Q000097:blood* / Q000652:urine; D003924:Diabetes Mellitus, Type 2 / Q000097:blood / Q000503:physiopathology*; D005260:Female; D006801:Humans; D007328:Insulin / Q000097:blood / Q000378:metabolism*; D000078790:Insulin Secretion; D007515:Islets of Langerhans / Q000378:metabolism / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged
chemical_list: D002096:C-Peptide; D007328:Insulin