Republican state Sen. Wayne Kuipers formally launched his bid for Michigan’s open 2nd District seat on Saturday, where a competitive GOP primary is expected to determine the next congressman in the heavily Republican Western Michigan district.

Kuipers, who is serving his second term in the state Senate after two terms in the Michigan House, joins three other GOP candidates in the race: former three-term state Rep. Bill Huizenga; former NFL player and University of Michigan tight end Jay Riemersma ; and businessman Bill Cooper.

Nine-term Rep. Peter Hoekstra is leaving the seat open to run for governor in 2010.

Riemers posted an early fundraising lead in the race through Sept. 30, though half of his receipts came from a personal loan.