Inhibition of temperature-dependent immobilization of fowl spermatozoa at body temperature by an increased intracellular pH

Fowl sperm motility was measured by altering the extracellular pH (pH e ) at 30 o C and 40 o C. At 30 o C, the motility of intact spermatozoa was vigorous in a medium in the wide pH e range of 7.3-10.1. In contrast, intact spermatozoa were almost immotile at 40 o C in medium below a pH e of 8.1. However, the motility could be restored by increasing the pH e ; maximum motility was obtained in medium at pH e 9.4. Stimulation of the motility of demembranated spermatozoa at 40 o C was also observed with an increased pH e