Quinacrine accumulates in certain peptide hormone-producing cells

Area of Science:

• Pharmacology
• Cell Biology
• Endocrinology

Background:

• Quinacrine is a fluorescent acridine derivative with anti-malarial properties.
• It exhibits selective binding to specific neuronal and endocrine cell populations.

Purpose of the Study:

• To investigate the cellular localization and fluorescence kinetics of quinacrine in peptide hormone-producing cells.
• To explore the potential of quinacrine fluorescence as an indicator of secretory granule turnover and cellular activity.

Main Methods:

• Selective binding assays of quinacrine to various cell types.
• Fluorescence microscopy to visualize quinacrine localization.
• Measurement of fluorescence half-life in different cell populations.

Main Results:

• Quinacrine selectively binds to peptidergic nerves and peptide hormone-producing cells, including those in the adenohypophysis, thyroid (calcitonin cells), pancreatic islets (insulin, glucagon, PP cells), and pyloric antrum (gastrin cells).
• The fluorophore accumulates within secretory granules.
• Fluorescence half-life varies significantly between cell types, ranging from 6 hours in gastrin cells to 40 hours in insulin cells.

Conclusions:

• Quinacrine's selective accumulation in secretory granules suggests its utility as a marker for these organelles.
• The varying fluorescence half-life across cell types may reflect differences in secretory granule turnover rates.
• Quinacrine fluorescence disappearance kinetics could potentially indicate cellular secretory activity.