Make insistent demands on section of media (5)
I believe the answer is:
press
I believe this clue is a double definition.
'make insistent demands on' is the first definition.
'section of media' is the second definition.
(Other definitions for press that I've seen before include "Fourth estate" , "Crush; iron" , "rags together" , "Squeeze out (juice/oil)" , "Cupboard for storing clothes" .)