WASHINGTON (AP) _ Former college first baseman George Bush, an avid baseball fan, threw out his first ball as president today at the season-opener between the Baltimore Orioles and the Boston Red Sox.

Bush took Egyptian President Hosni Mubarak to Baltimore's Memorial Stadium for the afternoon game after a private work session in the Oval Office.

Under sunny skies, Bush threw the first ball to Orioles' catcher Mickey Tettleton. Left-hander Bush's pitch was a little high and outside but Tettleton had no problem snatching it with a long reach.

In a series of sessions with leaders from the Middle East, the president plans to meet with Israel Prime Minister Yitzhak Shamir on Thursday, and with Jordan's King Hussein later in the month.

Meanwhile, the president met today at the White House with families of the victims of the Pan Am Flight 103 disaster. The jumbo jet was ripped apart by a terrorist bomb Dec. 21, killing all 259 people aboard and 11 on the ground in Lockerbie, Scotland.

Bush ''expressed his sorrow and deep concern with respect to the families of the victims of this tragic incident,'' the White House said in a statement released after a more than hour-long session. ''The meeting was sensitive, solemn and productive.''

Bert Ammerman of Riverdale, N.J., chairman of a political action committee established in the memorie of the Lockerbie victims, told reporters the meeting represented ''an important first step'' in bringing comfort to the victims' relatives and toward ensuring increased aviation security.

''The truth must be known,'' said Ammerman, who told reporters he asked Bush to consider a single, unified independent investigation by Congress.

Bush, captain of Yale's 1948 baseball team, threw out many first balls during his eight years as vice president and during last year's presidential campaign.

Initially, Bush had been expected to throw out the first ball in Cincinnati in the season opener between the Reds and World Series champions the Los Angeles Dodgers.

However, Mubarak's visit along with other scheduling problems prompted the decision to pick a game closer to home.

Sources, who spoke on the condition of anonymity, said the gambling investigation hanging over the head of Reds manager Pete Rose played no part in the decision to have Bush go to Baltimore instead.

Meanwhile, first lady Barbara Bush on Sunday reverted to her ''silver fox'' image as she appeared in public without the brown wig that had stunned and delighted an annual journalists' banquet on Saturday night.

Mrs. Bush nearly stole the show at Saturday night's annual Gridiron dinner when she appeared with Bush in a honey brown wig that hid her trademark head of snowy hair.

The wig was gone when the Bushes attended an early-morning worship service at the Washington Cathedral, and again later when the first couple went to lunch at the Washington home of syndicated columnist Charles Bartlett.

The wig ''was just a joke,'' Mrs. Bush's press secretary, Anna Perez, insisted Sunday. She said Mrs. Bush is happy with her own hair and has no intentions of wearing the wig again.

''It came from a mail-order catalogue,'' Ms. Perez said. She said Mrs. Bush had ordered the ''average-priced'' wig from a shop in California and that even the president ''found out about it very late.''

''You can't take criticism too seriously,'' the president said on Saturday. ''Barbara neither noticed nor reacted to all that talk about her white hair.''

Bush was lampooned by the journalistic establishment at the annual dinner of the 104-year-old Gridiron Club.

He returned the barbs with a few of his own, many of them directed at himself. At one point he deadpanned: ''People say I'm undecisive. I don't know about that.''

Vice President Dan Quayle, who also was the target of many of the group's jokes, told the audience of 600 invited guests that Bush had recently praised his maturity and sense of responsibility by asking him: ''Would you like a puppy?'' from first dog Millie's litter of six pups.