Development of glucose-mediated insulin release response in organ cultured rat pancreas

In the Sprague-Dawley rat, glucose concentration dependent insulin release first appears 2 days after birth. If pancreatic explants from 19-, 20- or 21-day fetal rats are organ cultured to a period corresponding to the 4th postnatal day, 120 min stimulus with glucose (100 or 300 mg/dl) fails to produce glucose-dependent insulin release. When explants from 20-day fetal pancreas are cultured, glucose-mediated insulin release develops after 12 h to 2 days of culture, and persists for up to 2 days. Explants from 3 day postnatal pancreas retain glucose-dependent insulin release for at least 2 days culture. High tissue insulin levels and continued release of immunoreactive insulin into culture medium are maintained throughout the culture period studied. Our data show that glucose-mediated insulin release can develop in organ culture, and suggest that this development, after the 19th fetal day, does not require extrapancreatic neural or endocrine factors.