Regulation of internal pH of sea urchin sperm. A role for the Na/K pump

• Published in: The Journal of biological chemistry 1985-06, Vol.260 (12), p.7599-7602
• Main Authors: Gatti, J L, Christen, R
• Format: Article
• Language: English
• Subjects: Ammonia - pharmacology; Animals; Biological and medical sciences; Early stages. Segmentation. Gastrulation. Neurulation; Embryology: invertebrates and vertebrates. Teratology; Fundamental and applied biological sciences. Psychology; Hydrogen-Ion Concentration; Kinetics; Lithium - pharmacology; Male; Ouabain - pharmacology; Potassium - pharmacology; Rubidium - metabolism; Sea Urchins; Sodium - pharmacology; Sodium-Potassium-Exchanging ATPase - metabolism; Spermatozoa - metabolism
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1016/S0021-9258(17)39650-3

In the absence of sodium, sea urchin sperm have an acidic internal pH. The addition of sodium, lithium, or ammonium, but not of potassium ions, induces an internal alkalization. If potassium is added in the presence of sodium, a further alkalization is obtained; in contrast, potassium addition in presence of Li+ or NH+4 does not change the internal pH. The K+-induced pHi change is inhibited by ouabain and when sperm are depleted of their ATP. A large part of the potassium influx is stimulated by Na+, but not Li+, and inhibited by ouabain and cellular ATP depletion. We conclude that activity of Na/K-ATPase pumps located in the plasma membrane of sea urchin sperm could play a role in regulating the internal pH of sea urchin sperm by recycling sodium ions that enter the cell through Na/H countermovements.