M. ChulavatnatolT. EksittikulP. ToowicharanontMahidol University2018-06-012018-06-011978-01-01International Journal of Andrology. Vol.1, (1978), 629-63813652605010562632-s2.0-85005560538https://repository.li.mahidol.ac.th/handle/20.500.14594/13107Thermal immobilization was designed as a simple approach to study factors controlling sperm motility. Heating dissected epididymis or isolated epididymal sperm at 48°C to 52°C for 5 min abruptly and completely immobilized the sperm. The thermally immobilized sperm showed some alteration of membrane lipids, as indicated by the response of the surface ATPase to temperature change. However, no qualitative change in the surface negative charge was detectable by the binding of the cells to DEAE‐Sephadex beads. The immobilized cells can metabolize ATP into ADP and AMP similar to the control epididymal sperm. The ATP‐dependent sliding or disintegration of sperm flagella was completely prevented in the immobolized cells. The findings suggested that heat‐treatment disrupted the integrity of the sperm membrane and the motile apparatus, resulting in the loss of sperm motility. The development of post‐testicular antifertility agents should aim at interfering specifically with these components of the sperm. Copyright © 1978, Wiley Blackwell. All rights reservedMahidol UniversityMedicineArticleSCOPUS10.1111/j.1365-2605.1978.tb00513.x