Mayor George Moscone, who celebrated his job with the enthusiasm of a kid opening Christmas presents, was buried today in the city he loved so openly.

His four children, square-shouldered and fighting tears, stood at the altar of St.Mary's Cathedral this morning and took turns reading aloud to the 5,000 mourners crowded inside for the funeral mass of the murdered mayor. A section of pews in the stark, modern cathedral was filled with mayors and other public officials, who came from as far as Boston and Anchorage to honor their colleague.

It was the second time in eight days that stunned public officials from across the country have gathered in the San Francisco area to mourn a murdered colleague. Rep. Leo J. Ryan (D-Calif.) was buried near here on Nov. 22, the 15the anniversary of President Kennedy's assassination, four days after Ryan and four others were shot to death while waiting to leave Port Kaituma, Guyana, after visiting the Peoples Temple settlement.

Mayor Moscone attended that funeral trying as hard as his constituents to adjust in some way to the horror of each day's revelations about Guyana. The solemnity was uncharacteristic for him. Joking with reporters, cheering up colleagues, and repeating whenever the delight of it came over him, "I love being mayor of San Francisco," the man being remembered today, even by his many political critics, was one of enormous optimism and compassion.

"He was a man who strove to be warm, gentle, and kind to everyone," said Msgr. Peter Armstrong, rector of a Catholic boys' school near San Francisco, who spoke at the request of the Moscone family. "He possessed the rare quality of being able to talk to people and have them feel that they were important and dignified human beings."

The mourners included Mayor Maynard Jackson of Atlanta; Mayor Coleman Young of Detroit; John Lindsay, former mayor of New York City; Calif. Gov. Edmund G. (Jerry) Brown Jr.; former San Francisco mayor Joseph Alioto; dozens of state senators and representatives and thousands of the stricken San Franciscans for whom the past eight days have become one long effort to cope with grief.

Ever since Monday morning, when Moscone and Supervisor Harvey Milk were shot to death within minutes of one another in offices at City Hall, mental health and suicide prevention centers have been adjusting to a sharp increase in requests for help -- an increased workload made harder by the fact that the counselors sometimes have been almost as depressed this week as the people they are trying to help.

"It's just like the loss of a big daddy or something," said Claudius Williams. brother of the pastor at Glide Memorial Church, where 60 extra volunteers came in Monday and Tuesday to answer crisis line telephones and to seek solace from each other.

A woman who works with suicide prevention and mental health crisis counseling said there had been a slight increase in suicide calls and about triple the number of usual calls on the mental health lines. "Yes, we have had an increase in phone calls, but, no, the people who call are not killing themselves," she said. "They're expressing their feelings of grief, of confusion over the events of the last two weeks."

Massive publicity has surrounded the two murders, especially because the suspect, a former supervisor named Dan White who had resigned his seat and badly wanted it back, walked into the mayor's office in front of several witnesses and was alone with the mayor just before Moscone was found shot to death.

Wednesday's San Francisco Examiner carried reports that police testing showed White's .38-cal. revolver to be the one used in the killings; today's San Francisco Chronicle -- under a banner that read "Dan White Confesses" -- quoted sources as saying White had "laid it all out" to police.