The House voted, 391 to 25, yesterday in favor of an amendment to authorize an additional $175 million in non-food aid for famine-stricken African countries.

The $175 million emergency measure authorizes funding for medical supplies, clothing, shelter and other disaster and refugee assistance. It is part of a $880 million emergency spending package for African famine victims that is expected to come up for a House vote Thursday.

The price tag on the African aid package is more than three times the amount requested by the administration.

Rep. W. Henson Moore (R-La.) yesterday became the first announced candidate for the seat now held by Sen. Russell B. Long (D-La.). Long, who has been in the Senate for 36 years, announced unexpectedly Monday that he will retire when his term expires in 1986.

Moore, who is in his fifth term in the House, said he had been thinking about running for the Senate before Long announced his retirement and has raised $750,000.

Two Democratic members of the Louisiana House delegation, Reps. Buddy Roemer and John B. Breaux, are said to be considering running for Long's seat.

Secretary of State George P. Shultz became irritated with persistent questioning on "Nazi-like atrocities" by the Soviets in Afghanistan during his appearance before the Senate Armed Services Committee yesterday.

Sen. Gordon J. Humphrey (R-N.H.) attacked the administration for failing to link Soviet behavior in Afghanistan to arms control and for not speaking out more loudly about Soviet tactics.

"I'm not hedging," Shultz told Humphrey, his voice rising in apparent anger. "You want to turn everything into black and white. It isn't that way. I'm saying it is a mistake to get yourself into a position where everything in the world hangs on one thing."

"Do you think it's wise to submit the security of the United States and the West to a treaty whose co-signatory is a nation conducting criminal activities against a largely defenseless people?," Humphrey asked.

"Come off it senator," Shultz said.

About 135 House Democrats and their families are to gather at the swank Greenbrier Hotel in the hills of West Virginia this weekend for a sort of political encounter session.

The issues conference, organized by House Democratic Caucus Chairman Richard A. Gephardt (D-Mo.), is intended to help the Democrats work better as a "team" and communicate the party's message more effectively. Its meetings and speeches are closed to the news media.

Among the topics for discussion: "The Spark to Light the Explosion," a speech by motivational expert Lou Tice, who is also to lead a workshop entitled "Words in Themselves Have No Power."

Others speakers will be Lee Iacocca, chairman of the Chrysler Corp., on "Where Does America Go From Here?"; former Reagan White House communications director David R. Gergen on "Communications and Politics," and former Carter administration Navy undersecretary James Woolsey, who will conduct a national security workshop.

The event is being underwritten and run by the National Legislative Education Foundation, through contributions from individuals, corporations and labor unions, according foundation officials. In addition, each lawmaker will pay $400.