productions were linear functions of time for 120 min and were decreased as extracellular ph was increased from 7.0 to 7.5 to ascertain whether activation of protein kinase c affects either process , we incubated segments with tumor-promoting phorbol esters , 12-o-tetradecanoylphorbol-13-acetate ( tpa ) , or phorbol 12,13-dibutyrate , or with the inactive phorbol ester 4 alpha-phorbol .
C0039654
12-o-tetradecanoylphorbol-13-acetate
C0031586
phorbol ester