Associated Press, 08/07/99 18:43

      Joe DiMaggio Jr., the troubled son of the baseball Hall of Famer and a pallbearer at his father's funeral in March, died at a hospital in Antioch, Calif., apparently of natural causes, relatives and hospital officials said Saturday. He was 57.
      DiMaggio was not breathing and had no heartbeat when he was brought by ambulance to Sutter Delta Medical Center late Friday night, hospital spokeswoman Nancy Monfort said. Attempts at resuscitation were unsuccessful and he died about 11:25 p.m. Friday.
      Though Monfort said the cause of death was not known, it was believed to be from natural causes.
      DiMaggio was the only child of Joe DiMaggio and Dorothy Arnold, an actress whom the elder DiMaggio married in 1939 and divorced five years later. The elder DiMaggio did not have any children with his second wife, Marilyn Monroe.
     Joe Jr., who struggled with substance abuse and homelessness during the last two decades, was estranged from his father and saw him infrequently in recent years. He was divorced and had two adopted daughters who were doted upon by their grandfather.
      For many years, both father and son had refused to answer questions about their relations.
      Marie Amato Goodman, a cousin whose son was a close friend of the younger DiMaggio, said the son was unable to cope with his father's fame.
      ''He had a brilliant mind. He was one of the intelligentsia,'' Goodman said. ''He lived in the shadow of his father and could not rise above that.
      ''He marched to a different drummer. He was very sensitive to the people close to him,'' she said.    ''He really was not a bad boy. He was confused about a lot of issues in his life.''
      Morris Engelberg, a close friend and attorney for the elder DiMaggio, said, ''It's very sad. He loved his father. He turned down a seven-figure offer to do a book about Joe, as much as he could have used the money. He was broke.''
      Engelberg said Joe Jr. had suffered from asthma.
      DiMaggio attended Yale, but dropped out to enroll in the Marines. In the mid-1970s, he had a blood clot removed from his head following a car accident. During the past two decades, he battled drug and alcohol problems. He often lived alone on the street, and took shelter at one point in a trucking container. For a while, he was the manager of a trucking company in Oakland.
      In September 1995, he fractured his leg when the bicycle he was riding hit a van. He had a permanent limp after the accident, and was cited by the California Highway Patrol for operating a bicycle under the influence of alcohol.
      It was unclear where he was living and if he was working at the time of his death. The hospital in Antioch is 37 miles northeast of San Francisco.
      Joseph DiMaggio Jr.'s middle name was Paul, the same as his father and uncles, Vince and Dominic, both of whom also played in the major leagues. Joe DiMaggio Sr. once explained, ''Saint Paul was my father's favorite saint.''
      The younger DiMaggio and his wife, Susan, adopted daughters Paula and Katherine in the 1960s, but the marriage collapsed after six years.
      The elder DiMaggio set up a trust fund that was to pay his son $20,000 a year. The bequest, in a will signed May 21, 1996, appeared to be the smallest gift in the document, which also established trust funds for DiMaggio's two grandchildren and four great-grandchildren.