California Senate President Pro Tem Don Perata (D-Oakland) intervened in a dispute with regulators to help a West Hollywood company maintain lucrative billboards on freeways in Los Angeles and Orange counties, records show.

Perata intervened in 2001 the day after the company, Regency Outdoor Advertising Inc., reported giving a $25,000 campaign contribution to a Perata-backed initiative. The company's co-owner said the contribution came in response to a request from the senator...