Rowe quit her post as executive director of communications earlier this week after just ten months heading the GLA's communications function.
She is understood to be returning to the private sector, but was unavailable for further comment as PRWeek went to press.
A GLA spokesman said: 'Her departure is something she's been considering for a while having found the transition to the public sector not quite what she had hoped.'
On her successor, he added: 'There have been no decisions made yet. It will be discussed by the GLA chief executive Anthony Mayer, London Mayor Ken Livingstone and the Greater London Assembly.'
Rowe joined the GLA last December from the London Tourist Board and Convention Bureau, where she acted as director of communications.
At the GLA she was responsible for overseeing a communications budget of more than £1m.
Her brief included advertising, public liaison and consultation, development of web content and internal communications.
During her time with the GLA, Rowe also launched a campaign to gain a higher national profile of Livingstone. In May, the authority hired former Labour Party communications director Joy Johnson from public affairs agency GPC to head media relations.
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