A Labor Department employe pleaded guilty in U.S. District Court yesterday to attempting to gain sexual favors from a woman in exchange for approval of her requests for grants of federal job funds.

Glendon E. Whitman, 44, of Lorton pleaded guilty to a misdemeanor charge of using a federal office to gain something of value. Whitman, a manpower development specialist whose job included approving federal jobs funds for American Indian reservations in three states, faces one year in jail, a $500 fine or both.

Justice Department attorney Steven A. Shaw said in court yesterday that Whitman told the woman, who directed a jobs program on an Indian reservation in Minnesota, that he would withdraw all her grant funds and cause her to lose her job if she refused his demands for sex.

Shaw said in court that the woman, who rejected Whitman's sexual advances, was fired from her job in December 1979 after Whitman told her supervisors that their grants would not be renewed unless she was dismissed.

The woman, identified in court papers as Kathryn Defoe Leimer, did not inform her supervisors of her conversations with Whitman. The incidents came to the attention of Justice Department officials only after she mentioned them to a friend.

Shaw, who is with the Justice Department's public integrity section, said in court that Leimer's supervisors were satisfied with the quality of her work but fired her solely because they feared Whitman would not renew their grants.

Neither Whitman nor his attorney contested the government's statements during yesterday's hearing, but Whitman's lawyer, James L. Lyons, said later that Whitman would dispute the allegation that his remarks to the supervisors caused the woman to be fired.

Whitman, who was in charge of approving grant proposals under the Comprehensive Employment and Training Act, was suspended from his GS-13 job at the Labor Department on Sept. 21, Shaw said during a hearing before U.S. Magistrate Arthur L. Burnett.

Leimer, who was CETA director at the Minnesota reservation, worked in clerical and secretarial jobs there for a few weeks after she was fired but has been unemployed since early 1980, he said.

The Justice department said in court papers that the charge against Whitman arose from an incident at a CETA workshop in Kansas City in August 1979 when, according to the papers, Whitman forced his way into Leimer's hotel room, made advances to her, refused to leave, and grabbed Leimer by the throat and shook her when she began to scream.

Shaw said that the government's evidence would show that Whitman left the room after Leimer told a telephone caller that she needed help, but told her that he would "pull all your funds" if Leimer continued to reject his advances.

Whitman told Burnett yesterday that he was intoxicated that evening but that he remembered making the remarks about sex and threatening to cut off Leimer's grant money. His lawyer said after the hearing that Whitman would dispute the allegation that he grabbed Leimer by the throat.

Burnett scheduled sentencing for Oct. 29.