Caffeine-stimulated ATP-reactivated motility in a detergent-treated bovine sperm model.

Mammalian sperm cells contain most of the components of a cyclic AMP-mediation system. To determine if the cyclic AMP-dependent protein kinase has a role in the control of bovine sperm motility, a sperm model was developed that was permeable to exogenously added ATP. Treatment of bovine epididymal spermatozoa with dithiothreitol and Brij-35 (polyoxyethylene alcohol), a nonionic surfactant, resulted in a sperm model with caffeine-stimulated, ATP-reactivatable motility. The results of the data obtained using this sperm model can be summarized as follows. (1) Brij partially solubilized the cyclic AMP-dependent protein kinase activity and released nearly half of the total acid-extractable nucleotides of the cells. (2) Brij treatment severely damaged the sperm mitochondria as judged by their lack of respiration. (3) Brij-treated spermatozoa lose their motility but were reactivated with ATP; the reactivated motility was stimulated by caffeine. (4) Despite the caffeine stimulation of motility in Brij-treated spermatozoa, increased protein phosphorylation did not accompany reactivation of motility, nor could a cyclic AMP effect be demonstrated on reactivated motility or on kinase activity in the sperm model.