Abortion and a fast-growing Republican electorate are the main catalysts in the Nov. 6 general election state legislative races that are emerging as Montgomery County's most fiercely contested political campaigns.

In those parts of the eastern and western ends of the county designated as Districts 14 and 15, respectively, there has been a surge of Republican enrollments -- an increase that helped elect Republicans from both districts to the House of Delegates four years ago. Both districts have also been targeted by state abortion rights activists who want to keep the Senate seats held by those favoring their position and pick up seats in the legislature's other chamber.

Those factors promise to make for especially interesting political battles in District 15, where three House of Delegates seats are at stake, and in District 14, where incumbent Democratic Sen. Edward J. Kasemeyer faces a strong Republican challenge.

Elsewhere in the county, it appears that incumbent legislators are favored in their reelection bids.

There is no Senate contest in District 18, where Del. Patricia R. Sher (D) won a crushing victory in the Sept. 11 primary, and none for the three House of Delegates seats in District 20, encompassing parts of Silver Spring and Takoma Park.

"District 15 is where the excitement is," said state Sen. Laurence Levitan who faces a challenge there from Republican lawyer Robert Miller.

Levitan, 56, who heads the Senate's influential Budget and Taxation Committee, is seen as a favorite for a fifth term. Miller, 54, is trying to challenge Levitan's influence in Annapolis by running on a platform asserting that the county hasn't gotten its fair share of state tax revenue.

Miller opposes abortion-rights legislation, while Levitan is heading a "Choice Team" ticket of abortion-rights supporters that seeks to capitalize on the issue. Abortion proved such a potent issue in last month's Democratic primary that four abortion opponents lost their Senate seats.

Joining Levitan on the ticket are Del. Gene W. Counihan, 49, Bethesda lawyer Rosemary Glynn, 45, and Potomac political activist Sally McGarry, 56.

They face Republicans Del. Jean W. Roesser, 60, builder Richard LaVay, 37, and Michael J. Baker, 27, an insurance claims adjuster from Damascus.

The three have joined Republican Nancy Dacek, who is seeking the County Council seat in District 2, which roughly embraces the same boundaries as the 15th District, on a ticket called "The Prime Team for the 90s."

Explaining why Senate candidate Miller is not included in the ticket, Roesser said the delegate candidates and Dacek campaigned during the primary and developed their own comfortable alliance. Miller did not have a primary contest.

In back-to-back news conferences earlier this month, each ticket staked out its territory.

Speaking for abortion rights-minded Democrats, Levitan said, "Past voting records and statements of Republican candidates in District 15 are not pro-choice and are not supported by pro-choice organizations."

Meanwhile, Republicans hammered on the theme of the evil of one-party rule: "We need to send representatives to Annapolis who speak for the people and not for the Democrat power brokers," said LaVay.

Roesser and her Republican running mates criticized the Democrats for singling out one issue.

She said it was especially inappropriate coming from Levitan and Counihan, who, because of their posts on key fiscal committees, should realize the threat Montgomery faces from changes in the state tax system being considered by a special commission.

The Republicans also argued that the Democrats have misrepresented their position on abortion.

"We all believe in choice," said LaVay, who said he would vote to sustain the Supreme Court's historic 1973 Roe v. Wade decision.

Baker has said he supports a woman's right to an abortion only during the first trimester of pregnancy.

The abortion issue has placed Roesser on the defensive.

She says she is not an extremist on either side of the issue. She said she is personally opposed to abortion, but would not vote to make it illegal in the first trimester.

Abortion-rights advocates point to her vote in her last term to restrict public funding for abortions and her abstention on a bill designed to prevent abortion protesters from blocking access to medical facilities.

Abortion rights advocates also have targeted District 14, where Kasemeyer, 45, who has spent eight years in Annapolis, faces a spirited challenge from Chris McCabe, a 34-year-old Republican. McCabe, a development officer for Johns Hopkins University's medical school and hospital in Baltimore ran against Kasemeyer in 1986, receiving 46 percent of the vote.

Kasemeyer is an advocate of abortion rights, while McCabe opposes abortion except in the case of rape, incest or if the mother's life is in danger.

McCabe said he believes that abortion will not be as powerful an issue in the general election as it was in the primary because of Gov. William Donald Schaefer's long-awaited position statement on the issue. After a four-year silence, Schaefer said after the primary that he would veto any legislation that would restrict a woman's right to an abortion.

On other matters, McCabe is stressing the problems of fast growth. Kasemeyer is emphasizing his experience in Annapolis and said he is best suited to deal with the delicate balance between economic growth and environmental protection.

In the race for the delegate seat that represents the Montgomery portion of District 14, Del. Joel Chasnoff, 51, seeking his fifth term, is opposed by Republican Pat Faulkner, 45, an insurance agent and a political activist who opposed him in 1986.

The two delegate seats that represent parts of Howard and Montgomery are now held by Republicans Robert L. Flanagan, 45, and Robert H. Kittleman, 64. They are being challenged by Democrats Lloyd G. Knowles, 56, a former member of the Howard County Council, and James B. Kraft, 41, a lawyer.

Here's a look at races in Montgomery County's other legislative districts: District 16

State Sen. Howard A. Denis, 50, a Republican who has served 14 years in the Senate and whose moderate-to-liberal voting record has proved popular in his Bethesda-Chevy Chase district, is seen as a favorite over Democrat Charles F. Chester, 36, a lawyer.

Both candidates favor abortion rights and, while Chester has tried to paint himself as more liberal, Denis has been backed by major abortion-rights groups for supporting their position in Annapolis.

In the delegate races, incumbent Democrats Brian E. Frosh, 44, Gilbert J. Genn, 38, and Nancy K. Kopp, 46, are challenged by George Jenkins, 63, a retired Army major and civil servant; lawyer Robert M. McCarthy, 35; and Nelson Rosenbaum, 43, a Bethesda businessman.

Jenkins is the only black person running for the legislature in Montgomery. District 17

Democrat Mary H. Boergers, 44, a two-term delegate who beat incumbent state Sen. S. Frank Shore in a Democratic primary dominated by the abortion issue, faces Republican William J. Skinner, 51, a pharmacist and lawyer, in a low-key race for the Rockville-Gaithersburg Senate seat. Both candidates favor abortion rights. Skinner once ran unsuccessfully for the County Council and Boergers is seen as having the advantage of name recognition in an overwhelmingly Democratic area.

Seeking reelection to the House are Democrats Jennie M. Forehand, 54, and Michael R. Gordon, 43, chairman of the county delegation. Kumar Barve, 32, a financial analyst and political newcomer who won a crowded Democratic primary, fills out the ticket.

Two Republicans are running, Torin K. Andrews, 30, a lawyer, and David S. Green, 31, a freelance writer and editor. District 18

This Silver Spring and Kensington district was the scene of a bitterly fought Democratic primary, but Nov. 6 sees no state Senate contest and a nominal Republican challenge for the House of Delegates.

The Democratic candidates who are seen as heavy favorites are incumbent Del. Patricia H. Billings, 53; John Hurson, 36, a lawyer; and Christopher Van Hollen Jr., 31, senior legislative adviser to Schaefer.

The Republicans are John Joseph Heil, 60, a retired military officer and economist, and Jamie M. Staines, 26, co-owner of a landscaping service. District 19

The Democratic incumbents, headed by state Sen. Idamae Garrott, are seen as the favorites in this Wheaton area district that includes parts of Silver Spring and Rockville. Running for reelection with Garrott, 73, are incumbents Henry B. Heller, 49, Carol S. Petzold, 53, and Leonard H. Teitelbaum, 59.

Running on the Republican side for Senate is Herbert S. Rosenberg, 69, a self-employed sales representative. Republicans seeking the House seat are Tomas R. Estrada-Palma, 35, vice president of the Language Exchange and until recently a member of Maryland's Libertarian Party; Peter J. Tirinnanzi Jr., 31, a defense analyst and law student; and Raymond Beck, 57, an engineer and retired Navy captain.

District 20

The overwhelmingly Democratic makeup of this Silver Spring and Takoma Park district make it a hard place for Republicans to run -- and none are running against Democratic House of Delegates incumbents Dana Lee Dembrow, 37, Peter Franchot, 42, and Sheila Ellis Hixson, 57.

In the Senate race, incumbent Ida G. Ruben, 61, who won a bitter Democratic primary over a well-financed opponent, is considered the favorite over Republican Thomas R. Falcinelli, 55, a lawyer.