Background: Leydig cells, crucial for testosterone production, express ion channels like ANO1 that influence hormone secretion. This study investigates the expression and role of the Tandem of P domains in a weak inward rectifying K+ channel-related Acid-Sensitive K+-1 (TASK-1) channel in these cells, exploring its impact on testicular function and steroidogenesis. Methods: TASK-1 expression in Leydig cells was confirmed using immunostaining, while RT-PCR and Western Blot (WB) validated its expression in the TM3 Leydig cell line. The effect of a TASK-1 channel blocker on cell viability was assessed through live/dead staining and MTT assays. Additionally, the blocker’s effect on testosterone secretion was evaluated by measuring testosterone levels. Results: Immunohistochemical analysis revealed a predominant presence of TASK- 1, along with c-Kit and ANO-1, in Leydig cells adjacent to seminiferous tubules and also in Sertoli and spermatogenic cells. Expression levels of TASK-1 mRNA and protein were significantly higher in TM3 Leydig cells compared to TM4 Sertoli cells. In addition, blocking TASK-1 in TM3 cells with ML365 induced cell death but did not affect LHinduced testosterone secretion. Conclusions: These findings suggest that TASK-1 in Leydig cells is crucial for their viability and proliferation, highlighting its potential importance in testicular physiology.

INTRODUCTION
MATERIALS AND METHODS
    Chemicals
    Animals and testis isolation
    Hematoxylin and eosin (H&E) staining
    Immunohistochemistry (IHC)
    Cell culture
    Total RNA extraction
    Reverse transcriptase-polymerase chain reaction (RTPCR)
    Western blot analysis
    Live/dead cell staining
    Cell viability assay
    Measurement of testosterone concentration
    Statistical analysis
RESULTS
    TASK-1 is expressed in Leydig cells and Sertoli cellswithin the testes of mice
    TASK-1 is more highly expressed in TM3 cellscompared to TM4 cells
    Blocking TASK-1 induces death in TM3 cells
DISCUSSION
REFERENCES

• Min Seok Woo(Department of Physiology, College of Medicine and Institute of Medical Sciences, Gyeongsang National University, Jinju 52727, Korea)
• Eun-Jin Kim(Department of Physiology, College of Medicine and Institute of Medical Sciences, Gyeongsang National University, Jinju 52727, Korea)
• Anjas Happy Prayoga(Department of Physiology, College of Medicine and Institute of Medical Sciences, Gyeongsang National University, Jinju 52727, Korea, Department of Convergence Medical Science, Gyeongsang National University, Jinju 52727, Korea)
• Yangmi Kim(Department of Physiology, Chungbuk National University College of Medicine, Cheongju 28644, Korea)
• Dawon Kang(Department of Physiology, College of Medicine and Institute of Medical Sciences, Gyeongsang National University, Jinju 52727, Korea, Department of Convergence Medical Science, Gyeongsang National University, Jinju 52727, Korea) Corresponding author