U.S. Rep. John Olver, an Amherst resident and former University of Massachusetts professor who’s served in Congress for the past 20 years, announced yesterday that he would retire from his post at the end of his term in 2012 – a move that could shake up the drawing of congressional districts in Massachusetts as the state prepares to cut one of its sectors in redistricting measures.

Olver, D-District 1, said in a statement yesterday that while he had previously stated that he intended to serve in the U.S. House beyond the end of his current term, he decided to retire because of family matters.

“Last December, I announced that I intended to seek to continue my congressional service beyond 2012,” said Olver, 75, in the statement. “Over the past six months, circumstances within my family have substantially changed, and I now find I must reconsider my earlier decision.”

Olver, whose wife was diagnosed with cancer earlier this year, did not respond to an interview request last night and was not expected to release any further comment or statement to the media yesterday, an official at his office in Washington said last night.

A number of elected officials on both local and national political scenes, however, issued statements praising the 11-term congressman’s work after the news of his retirement was divulged yesterday.

“John Olver has proudly served the people of Massachusetts for over forty years,” said President Barack Obama in a statement last night. “He has fought tirelessly for a cleaner environment, modern infrastructure, more affordable housing, and more accessible health care. Michelle and I join the people of Massachusetts in thanking Congressman Olver for his service, and we wish John, his wife Rose, and daughter Martha the very best in the future.”

Gov. Deval Patrick and Sen. John Kerry also issued statements lauding Olver’s work in politics.

“Throughout his career, John Olver has served as a bastion of support for his constituents, friends and family in western Massachusetts,” said Patrick in a statement. “While his leadership in Congress will be missed, I know that his advocacy and passion for public service will continue, and Diane and I wish him the best.”

“My friend and longtime colleague John Olver is a quiet man who lets his large accomplishments speak for him,” added Kerry in his statement. “He’s a public servant of principle who has served western Massachusetts with great skill and deep passions belied by his unassuming and humble demeanor. All of those qualities are a great credit to this remarkable public servant. He’s been a congressional workhorse with the heart of an Amherst activist.”

But the news of Olver’s impending retirement could have a substantial impact in ongoing congressional redistricting measures in the state. The Commonwealth will lose one of its 10 congressional seats by the next election cycle due to a lull in population growth in the state compared to other parts of the country.

A local state representative interviewed last night said that while she didn’t know to what extent the news of Olver’s retirement would have on redistricting plans, it would certainly shake things up.

“I have no idea [what impact it will have], but it certainly is going to have an impact,” said state Rep. Ellen Story, D-Amherst, in a phone interview from her Amherst home last night. “Ideally, you have someone retire, so you don’t have congressmen running against each other.”

Story, who first heard the news of Olver’s retirement on the radio on her drive back from Boston yesterday, also said she wasn’t sure if the news would have a specific impact on the consolidation of districts in western Massachusetts.

“I hope that it doesn’t” have an impact in western Massachusetts, said Story, who also noted that she’s been an admirer of Olver for several years. “But I just don’t know.”

The redistricting measures are being spearheaded by the Special Joint Committee on Redistricting, a group that’s composed of members of the state Legislature. The committee is expected to release plans within the next few weeks.

Many, though, have speculated that redistricting measures could involve the elimination or consolidation of the First Congressional District.

State Sen. Stan Rosenberg, D-Amherst, the co-chairman of the special committee, did not return requests for comment on the matter last night. When reached by the Massachusetts Daily Collegian last night, Rosenberg’s partner – who picked up the phone at his residence – said that the Amherst Democrat, who he said was on his way back from Boston, would not be making comments to the media.

But Rosenberg, along with state Rep. Michael Moran – the other co-chairman of the committee – did release a brief joint statement yesterday on the news of Olver’s retirement and its potential impact on redistricting, saying that in the next few days the committee will examine what effect the development could have on plans.

“We wish the Congressman and his family well during his final year serving in Congress and wish them all the best in the future,” the statement read in part. “This is a dramatic change, and the Committee in the coming days will assess its impact on Congressional Redistricting.”

Currently, Olver represents constituents in areas stretching from Fitchburg to Pittsfield in a district that covers about a third of the land in the state.

The announcement of Olver’s retirement marks the end of a political career that’s stretched over 40 years.

Olver has served in the U.S. House since 1991, and previously served in the Massachusetts state Senate for 18 years prior. He also served in the Massachusetts state House from 1969 to 1973.

“Congressman Olver has made Amherst proud through his representation of the 1st Congressional District for 20 years,” Amherst Select Board Chairwoman Stephanie O’Keeffe said in a statement to the Collegian last night. “Not only has his leadership benefited us locally and in the region, but his wisdom has contributed to positive outcomes for so many issues on which Congress has influence, around the country and around the world.”

Olver currently serves on three committees in the House – including as a ranking member on the Appropriations Subcommittee on Transportation, Housing and Urban Development, and Related Agencies.

A chemist by training, he also served as a professor and taught chemistry at UMass in the 1960s. And, according to UMass spokesman Ed Blaguszewski, he’s aided the University and many educational programs throughout his years in politics.

“He’s had a lifelong impact on education … and has been a great friend of this Amherst campus for many years,” said Blaguszewski in a phone interview last night. “His legacy will endure UMass for many, many years.”

William Perkins can be reached at [email protected].