The United States is seeking to gain the release of Soviet dissidents Andrei Sakharov and Anatoly Scharansky through the mediation of Wolfgang Vogel, the East German lawyer who often acts as an intermediary in the exchanges of spies and political prisoners, western intelligence sources said.

American and West German officials have refused to divulge details about Vogel's role in secret negotiations or who initiated the contacts. But intelligence sources confirmed that Vogel is involved in negotiating terms for the freedom of Sakharov, the Nobel Prize-winning physicist, and Scharansky, a Soviet Jew and computer scientist.

An early release of the two renowned dissidents has acquired greater urgency because both of them are known to be in failing health. Scharansky, denied the right to emigrate to Israel to join his wife, was jailed seven years ago and is being kept virtually incommunicado. Sakharov, forced to live under internal exile in Gorki, was last seen in two film reels released in June undergoing medical treatment for serious heart and circulatory problems.

One of the difficulties that has apparently arisen in the surreptitious bargaining is a strong American reluctance to implicate the two dissidents in any deal that might brand them as traitors, the sources said.

It is believed the Russians are seeking an exchange for key spies held in the United States, but the administration wants to avoid equating Scharansky and Sakharov with foreign agents.

Several years ago, Vogel tried to arrange a swap of Scharansky for Guenter Guillaume, a trusted aide of chancellor Willy Brandt who was unmasked in 1974 as an East German spy, contributing to Brandt's downfall. Guillaume served seven years of a 13-year sentence before being released in a spy trade in 1981.

The intelligence sources said the release of the two Soviet dissidents does not appear likely before the summit meeting Nov. 19-20 between President Reagan and Gorbachev. But they suggested that doing so shortly thereafter could cushion disappointment from a potentially unsuccessful Geneva meeting dominated by conflicts over arms control.

Vogel, a confidant of East German leader Erich Honecker, has cultivated close contacts in Moscow and Washington by frequently serving as a conduit in human traffic between the two superpowers as well as the two German states.

Vogel's role in the current negotiation was first reported by the West German weekly news magazine Der Spiegel last weekend. The magazine cited no sources for its article, but one American official, describing Vogel as "something of a self-promoter," speculated that the lawyer himself might have leaked the story initially.

Last June, Vogel arranged the release of 25 East Bloc detainees accused of aiding western intelligence services. In a ceremony at Berlin's rickety Glienicker Bridge, they were delivered into the custody of Richard Burt, assistant secretary of state for European affairs and now U.S. ambassador to West Germany, in exchange for four East Europeans charged or convicted of espionage in the United States.

In Washington, State Department officials dealing with Soviet affairs said they have not heard Vogel's name mentioned in internal U.S. government discussions about Sakharov and Scharansky. However, the officials acknowledged that the plight of the two dissidents is what one called "an absolutely top priority, front-burner issue for us and one that we raise with the Soviets at every opportunity."

They said the cases of Sakharov and Scharanksy are raised by the United States in every bilateral meeting with Soviet officials. In addition, the officials added, the United States has assigned a high priority to obtaining all the information it can gather about the whereabouts and health of the two men.

Vogel's most spectacular exploit in spy swapping occurred in 1962, when he secured the trade at the same Glienicker Bridge of Francis Gary Powers, the U2 reconnaissance pilot shot down over the Soviet Union, for Col. Rudolf Abel, a top-ranking Soviet spy convicted in the United States.

Over the past two decades, Vogel, 59, has gained most notoriety by acting as broker for East German political prisoners or would-be expatriates whose release is paid for, often according to their professional rank, by the West German government.

More than 20,000 East Germans are believed to have gained passage out of jail to freedom in the West at a cost estimated as high as $1 billion. Originally Bonn paid for their release in scarce commodities, such as coffee, oil or machinery, but in recent years many transaction have been conducted in cash.

Freedom for a doctor or professor might cost as much as $100,000 while a laborer is sent to the West for as little as $10,000.

In his rare encounters with western reporters, Vogel has dismissed charges that he maintains a handsome income and friendships in powerful places by serving as a "flesh peddler."

He has said that his true motivation is to reunite divided German families and to earn compensation for the costs incurred by the East German socialist system in training and educating those who decide to leave for the West.