first, i've never heard of dvcprohd 50... there is a dvcpro50, but it is sd only (as far as i know) and there is dvcprohd, which is also often called dvcpro100.
do you mean that you need dvcprohd 1080/50 (50 fps, rather than 50Mbps), if so the dvcprohd codec that comes with fcp should do 1080/50i, and those same quicktime .movs from fcp will work in ae if ae is on the same machine as fcp.
if it is not on the same machine, you can move the dvcprohd quicktime component to another mac, but if you have a pc, then i think you'll need a utility to read/convert them (like raylight encoder pro) -- i don't think apple has included dvcprohd as a standard part of quicktime, only with fcp.
but it may be easier to just use an intermediate codec, like lossless mov, quicktime photojpeg or avid's dnxhd (free) which also works with quicktime. then you'd just export from fcp with one of those codecs, work with that in ae, render back to one of those and import back into fcp...