Abstract
Fetal (18 days postcoitum) and neonatal (3‐day) pancreatic explants were grown in organ culture with or without supplementation with corticosterone (0.1 μg/ml). After 0, 4, and 8 days of culture, the specific hormone‐positive, islet cell volumes were determined by the use of immunocytochemical and morphometric methods. The insulin, glucagon, and somatostatin contents of the explants were estimated by radioimmunoassays. In the fetal explants, all of the islet cell populations increased in volume and the content of each of the hormones increased over an 8‐day period of culture. Supplementation with corticosterone resulted in a restriction of the increases of the alpha and delta cell volumes and in the somatostatin content of the explants. In the neonatal explants, the volumes of the alpha and delta cells and the glucagon and somatostatin contents decreased over a 4‐day culture period. The presence of corticosterone in the culture medium preserved these cells and their hormone content. Co‐culture of 18‐day fetal and 3‐day neonatal pancreata in control medium for 8 days resulted in a significant decrease in the content of all three of the islet hormones in the fetal explants. These results suggest that a substance harmful to the islet cells is released from the degenerating acinar cells. Thus, the effects of the steroid on the islets may be mediated through its effects on the acinar tissue.