Résumé
The distribution of the prohormone convertases, PCI/3, PC2 and PC5/6, was determined by immunoblotting in two cell lines. In αTC1–6 cells, the proglucagon processing occured according to the pancreatic A-cell type. In STC-1 cells, proglucagon was processed in a manner reminiscent of the intestinal L-cell type. PC1/3 was undetectable in both proglucagon processing cell lines whereas PC2 displayed a strong immunostaining in the αTC1–6 cells and was barely detectable in the STC-1 cells. PC5/6 was detected as a 70 kDa protein in both cell lines. These results suggest a possible role of PC2 in the processing of proglucagon into glucagon in the A-cells, whereas in L-cells it would require still undetermined endoproteases.