Expression and function of ATP-dependent potassium channels in zebrafish islet β-cells

Area of Science:

• Endocrinology
• Molecular Biology
• Comparative Physiology

Background:

• ATP-sensitive potassium (K_ATP) channels are vital nutrient sensors in mammalian tissues.
• In pancreatic beta-cells, K_ATP channels link glucose metabolism to insulin secretion.
• The conservation of these metabolic sensing pathways in lower vertebrates remains largely uncharacterized.

Purpose of the Study:

• To investigate the expression and function of K_ATP channels in zebrafish islet beta-cells.
• To determine if zebrafish K_ATP channels are functionally conserved compared to mammals.
• To assess the impact of K_ATP channel activation on glucose homeostasis in zebrafish.

Main Methods:

• Analysis of K_ATP channel subunit composition and structure in zebrafish islet beta-cells.
• Functional assessment of native zebrafish K_ATP channels.
• Pharmacological activation of K_ATP channels using diazoxide.
• Evaluation of glucose tolerance in adult zebrafish following K_ATP channel activation.

Main Results:

• Zebrafish islet beta-cells express functional K_ATP channels with conserved subunit composition, structure, and metabolic sensitivity.
• Pharmacological activation of zebrafish K_ATP channels with diazoxide significantly impaired glucose tolerance.
• These findings highlight the evolutionary conservation of beta-cell K_ATP channel function.

Conclusions:

• Zebrafish K_ATP channels are functionally conserved with their mammalian counterparts, demonstrating evolutionary conservation of islet metabolic sensing.
• The zebrafish serves as a relevant model for studying islet glucose sensing and related diseases like neonatal diabetes.
• This research provides insights into the fundamental mechanisms of glucose homeostasis across species.