Fig. 5. BFA does not abrogate the PRL cleaving activity in acini-conditioned medium. Acini were incubated in the absence (lane -) or presence (lane +) of 5 µM BFA for 60 minutes at 37°C as described in Materials and Methods and the conditioned media used for assaying the PRL-cleaving activity. To this end, 2.5 µg/ml rPRL was added to the conditioned medium and after a 60 minute incubation at 37°C the samples were analysed by electrophoresis under reducing conditions and immunoblotting to reveal the PRL forms. The experiment demonstrates that the PRL-cleaving enzyme is present in the conditioned medium of BFA-treated acini. Positions of the molecular mass markers (kDa) are indicated on the left.