ABSTRACT
We compared the effects of phorbol-12, 13-dibutyrate on the acid release from unfertilized eggs with that from fertilized eggs of Lytechinus pictus and Pseudocentrotus depressus. The phorbol ester-induced acid release continued for more than 30 minutes and strongly depended on the existence of extracellular Ca in fertilized eggs, whereas in unfertilized eggs the acid release took place transiently and even in Ca -free media. Taken together with the results of pharmacological experiments using three kinds of protein kinase inhibitors, H-7, staurosporin and W-7, our results suggested that the phorbol ester-induced acid release may be mediated by the pathway containig protein kinase C.
