Measurement of circulating human proinsulin concentrations using a proinsulin-specific antiserum

C. F. Deacon, J. M. Conlon

Research output: Contribution to journalArticlepeer-review

28 Citations (Scopus)

Abstract

Antibodies have been raised against biosynthetic human proinsulin that show <1% cross-reactivity with human insulin and C-peptide. A sensitive (IC50 0.16 pmol/ml; minimum detectable concentration 0.004 pmol/ml) radioimmunoassay has been developed using this antiserum and 125I-proinsulin that will measure proinsulin-like immunoreactivity in human serum without the need for prior separation of insulin or C-peptide. In healthy, fasted subjects (N = 23), the serum proinsulin concentration was 0.015 ± 0.001 pmol/ml (mean ± SEM). In six healthy subjects, serum proinsulin rose to 250% of basal after 120 min in response to 100 g oral carbohydrate. The proinsulin/total immunoreactive insulin ratio and the proinsulin/C-peptide ratio fell sharply after both high and low carbohydrate loads. Endogenous human serum proinsulin-like immunoreactivity released into the circulation after 100 g carbohydrate was eluted from a Mono Q high-performance, ion-exchange column with the same retention time as biosynthetic human proinsulin. Treatment of biosynthetic proinsulin with trypsin under mild conditions led to a decrease in proinsulin-like immunoreactivity concomitant with an increase in C-peptide and insulin-like immunoreactivity, indicating that the proinsulin-specific antiserum did not preferentially recognize intermediates of proinsulin cleavage.

Original languageEnglish
Pages (from-to)491-497
Number of pages7
JournalDiabetes
Volume34
Issue number5
DOIs
Publication statusPublished (in print/issue) - 1985

Fingerprint

Dive into the research topics of 'Measurement of circulating human proinsulin concentrations using a proinsulin-specific antiserum'. Together they form a unique fingerprint.

Cite this