Here's a press release just sent out by Missouri senator Roy Blunt's office:

U.S. Senator Roy Blunt called U.S. Representative Todd Akin’s recent statements “totally unacceptable” and issued the following joint statement together with former Missouri U.S. Senators John Ashcroft, Kit Bond, John Danforth, and Jim Talent calling for Akin to step aside:   “We do not believe it serves the national interest for Congressman Todd Akin to stay in this race. The issues at stake are too big, and this election is simply too important. The right decision is to step aside.”

The only living current and former Missouri senators who have not called on Akin to leave the race are two Democrats: Claire McCaskill and Jean Carnahan. 

Update: Akin just told Mike Huckabee he will not exit the race.