Top dog announced (4)
I believe the answer is:
peak
'top' is the definition.
(I know that top can be written as peak)
'dog announced' is the wordplay.
'dog' becomes 'peke' (short for Pekingese).
'announced' indicates a 'sounds like' (homophone) clue.
'peke' sounds like 'PEAK'.
(Other definitions for peak that I've seen before include "Pointed mountain" , "Reach the highest point" , "Part of cap; mountain" , "High point" , "Acme" .)