Insulin and C-peptide (proinsulin) packaging: A quantitative immunocytochemical approach

✍ Scribed by Hammel, Ilan ;Kalina, Moshe

• Book ID: 102888133
• Publisher: Wiley (John Wiley & Sons)
• Year: 1989
• Tongue: English
• Weight: 707 KB
• Volume: 11
• Category: Article
• ISSN: 0741-0581
• DOI: 10.1002/jemt.1060110105

✦ Synopsis

C-peptide and insulin antigenic sites in rat pancreatic p cells were both labeled by the protein A and immunogold techniques. Gold bead density in the secretory granules was correlated with granule size distribution. Our results demonstrate that the distribution patterns of antigenic sites for C-peptide (which also represents proinsulin sites) and insulin are similar when granule size distribution is correlated to the density of antigenic sites. It was found that the ratio of C-peptide to insulin in granules is independent of granule size. Examination of frequency histograms by a Kolmogorov-Smirnov analysis excluded the possibility that the antigenic sites of C-peptide and insulin are distributed in the same manner. Mean gold bead density for insulin antigen (97 k 24) was slightly higher than C-peptide density (64 5 18). The efficiency of labeling was found to be very low; less than 0.1% of the theoretically estimated antigenic sites were labeled.