Distribution of Prohormone Convertase 1/3 in β and α Cells of the Human Fetal Pancreas at Gestational Weeks 8-20.

Data on the distribution of insulin biosynthesis enzymes in the developing human pancreas are limited and do not provide comprehensive understanding of mechanisms of β-cell maturation. In this study, the distribution of prohormone convertase 1/3 (PC1/3) in β and α cells of the pancreas of 15 fetuses (gestational age 8-20 weeks) was analyzed using double immunofluorescence staining. It has been demonstrated that numerous cells positively stained for PC1/3 but not containing insulin are present in the pancreatic islets during prenatal development. These cells probably represent maturing β cells that accumulate the enzyme prior to the insulin biosynthesis. In some of these cells, co-localization of PC1/3 and glucagon was revealed, which indicates a possible temporary expression of glucagon in differentiating and maturing β cells.