
I shot off a response to this last night that I've tried to cancel.  It was 
only a few minutes later while driving home that I remembered that your 
message does specifically say cortical.  My first reaction had been to suggest
the PC12 pheochromocytoma line.  That may still be a good compromise, depending
on what you're doing.  Have you concidered using a mouse cell line from one 
of the SV40 T antigen transgenic lines?  Another alternative might be primary
cells from bovine adrenal cortex.  