Insulin secretion from perifused rat pancreatic pseudoislets

Area of Science:

• Endocrinology
• Cell Biology
• Islet Biology

Background:

• Pancreatic islets are crucial for glucose homeostasis.
• Studying islet cell function requires intact islet structures.
• Dissociated islet cells can reaggregate to form pseudoislets.

Purpose of the Study:

• To investigate the spontaneous reaggregation of isolated rat islet cells into pseudoislets.
• To characterize the morphology and cell distribution within these pseudoislets.
• To evaluate the insulin secretory function of pseudoislets in response to stimuli.

Main Methods:

• Isolation and free-floating culture of adult rat pancreatic islets.
• Morphological assessment using light and electron microscopy.
• Immunofluorescent localization of islet cell types (A, B, D cells).
• In vitro perifusion studies to measure insulin release dynamics.

Main Results:

• Islet cells reaggregated into spherical pseudoislets resembling native islets.
• Ultrastructure and intercellular connections were well-preserved.
• A cells were peripherally located around a B cell core, with scattered D cells.
• Pseudoislets demonstrated biphasic, dose-dependent insulin release in response to glucose.
• Insulin release in response to L-arginine was biphasic but not dose-dependent.

Conclusions:

• Islet cells can reform functional pseudoislets with preserved morphology and cell organization.
• Pseudoislet B cells maintain nutrient-stimulated insulin secretion capabilities.
• These findings support the utility of pseudoislets as a model for studying islet function.