Testosterone modulates K(+)ATP channels in Sertoli cell membrane via the PLC-PIP2 pathway

Area of Science:

• Reproductive Biology
• Cellular Physiology
• Endocrinology

Background:

• Testosterone influences Sertoli cell function, including membrane potential and ion transport.
• Previous research suggests a role for ATP-sensitive potassium (K(+)ATP) channels in mediating testosterone's effects.

Purpose of the Study:

• To elucidate the specific signaling pathways through which testosterone affects Sertoli cell membrane potential and calcium uptake.
• To investigate the involvement of K(+)ATP channels and G protein-coupled phospholipase C (PLC) in testosterone's actions.

Main Methods:

• Electrophysiological recordings (membrane potential, input resistance) in immature rat Sertoli cells.
• Measurement of 45Ca2+ uptake.
• Pharmacological manipulation using testosterone, sulfonylureas, K(+)ATP channel modulators (diazoxide), pertussis toxin, and PLC inhibitors (U73122).

Main Results:

• Testosterone and sulfonylureas depolarized Sertoli cells, increased resistance, and enhanced 45Ca2+ uptake.
• These effects were blocked by diazoxide, pertussis toxin, and the PLC inhibitor U73122, indicating involvement of K(+)ATP channels and PLC signaling.
• Testosterone-induced reversal of hyperpolarization was also dependent on PLC activity.

Conclusions:

• Testosterone acts on Sertoli cell K(+)ATP channels via G protein-coupled PLC-phosphatidylinositol 4,5-bisphosphate (PIP2) hydrolysis.
• This signaling cascade leads to channel closure, membrane depolarization, and increased calcium influx.
• These findings clarify a key mechanism of testosterone action in testicular Sertoli cells.