Active cation transport in dog spermatozoa.

1. When dog semen is stored at 5 degrees for 24hr., K(+) is lost from the spermatozoa and Na(+) accumulates in the cells. 2. If at the end of the cold-storage period the semen is incubated at 37 degrees in the presence of added glucose there is a rapid uptake of K(+) and extrusion of Na(+) from the spermatozoa, the intracellular K(+) reaching a maximum within 30min. 3. When the semen is incubated at 20 degrees after cold storage there is an uptake of K(+) by the spermatozoa over 3hr. but no change in intracellular Na(+) concentration. 4. The extrusion of Na(+) and uptake of K(+) by dog spermatozoa has been shown to be inhibited by fluoride, iodoacetate, 2,4-dinitrophenol, and cetyltrimethylammonium bromide. 5. Uptake of K(+) is inhibited by ouabain and half maximum inhibition is obtained with a concentration of 50mmum. There is a slight stimulation of K(+) uptake in the presence of ouabain at about 0.3% of the concentration required for half maximum inhibition.