City office is loaded (5)
I believe the answer is:
laden
'is loaded' is the definition.
(I've seen this before)
'city office' is the wordplay.
'city' becomes 'la' (Los Angeles).
'office' becomes 'den' (I've seen this before).
'la'+'den'='LADEN'
(Other definitions for laden that I've seen before include "Like many a cargo ship" , "Loaded with cargo or burden" , "Eland (anag)" , "cargo aboard" , "packed with cargo" .)