Inhibition of transmembrane calcium influx induces decrease in proteoglycan synthesis in immature rat Sertoli cells.

Area of Science:

• Reproductive Biology
• Cellular Signaling
• Biochemistry

Background:

• Follicle-stimulating hormone (FSH) regulates Sertoli cells, involving cAMP and calcium signaling.
• Calcium influx plays a role in FSH-triggered signal transduction pathways.
• Sertoli cells synthesize proteoglycans, essential for testicular function.

Purpose of the Study:

• To investigate the role of intracellular calcium in regulating proteoglycan synthesis in Sertoli cells.
• To determine the effect of verapamil, a calcium channel blocker, on proteoglycan production.
• To elucidate the impact of calcium on proteoglycan metabolism and expression.

Main Methods:

• Cultured rat Sertoli cells from 20-day-old rats were used.
• [(35)S]-sulfate and [(3)H]-glucosamine incorporation measured proteoglycan synthesis.
• Verapamil and EGTA (calcium chelator) were employed to assess calcium's role.
• Quantitative solid-phase assay and pulse-chase kinetics analyzed proteoglycan levels and metabolism.

Main Results:

• Verapamil dose- and time-dependently decreased proteoglycan labeling.
• EGTA mimicked verapamil's effect, confirming calcium influx inhibition.
• Proteoglycan synthesis reduction was mainly due to impaired glycanation.
• Verapamil altered proteoglycan catabolism, affecting desulfation and retention.

Conclusions:

• Intracellular calcium is essential for maintaining Sertoli cell proteoglycan expression.
• Calcium influx inhibition impacts proteoglycan synthesis and metabolism.
• These findings suggest calcium's involvement in regulating Sertoli cell functions, potentially including estradiol production.