title: Proinsulin level in diabetes mellitus measured by a new immunochemiluminometric assay.
abstract: Proinsulin, the precursor of insulin and C-peptide, is detectable in the circulation and is a potential marker of beta-cell dysfunction. Currently, circulating proinsulin can be measured accurately without the interference of insulin or C-peptide by immunometric assays and a few specific radioimmunoassays. An immunochemiluminometric assay was developed in our laboratory by using two immunopurified polyclonal antibodies of C-peptide and insulin from two goats. The C-peptide antiserum was labeled with acridinium ester. The insulin antiserum was immobilized onto a plastic bead. With this assay, proinsulin levels found in noninsulin-treated patients with noninsulin-dependent diabetes mellitus (63 +/- 58 pmol/L; n = 19) were significantly higher (p < 0.05) than levels in insulin-treated patients with noninsulin-dependent diabetes mellitus (30 +/- 24 pmol/L; n = 43), and both were significantly higher (p < 0.001) than proinsulin levels in patients with insulin-dependent diabetes mellitus. In addition, there was a negative correlation between proinsulin levels and duration of years on insulin therapy in patients with noninsulin-dependent diabetes mellitus (r = -0.4795; p < 0.01).
authors.affiliation: Mayo Clinic Department of Laboratory Medicine and Pathology, Rochester, MN 55905, USA.
authors.forename: T J
authors.initials: TJ
authors.lastname: Wu
authors.forename: C L
authors.initials: CL
authors.lastname: Lin
authors.forename: R L
authors.initials: RL
authors.lastname: Taylor
authors.forename: P C
authors.initials: PC
authors.lastname: Kao
mesh_terms: D000328:Adult; D000368:Aged; D001786:Blood Glucose / Q000378:metabolism; D008076:Cholesterol, HDL / Q000097:blood; D003922:Diabetes Mellitus, Type 1 / Q000097:blood* / Q000188:drug therapy; D003924:Diabetes Mellitus, Type 2 / Q000097:blood* / Q000188:drug therapy; D005260:Female; D006801:Humans; D007118:Immunoassay / Q000379:methods* / Q000706:statistics & numerical data; D007328:Insulin / Q000627:therapeutic use; D008163:Luminescent Measurements; D008297:Male; D008875:Middle Aged; D011384:Proinsulin / Q000097:blood*; D012189:Retrospective Studies; D014280:Triglycerides / Q000097:blood
chemical_list: D001786:Blood Glucose; D008076:Cholesterol, HDL; D007328:Insulin; D014280:Triglycerides; D011384:Proinsulin