Sen. Edward M. Kennedy, ill with a brain tumor, was hospitalized Tuesday but quickly reported feeling well after suffering a seizure at a post-inauguration luncheon for President Barack Obama. “After testing, we believe the incident was brought on by simple fatigue,” Dr. Edward Aulisi, chairman of neurosurgery at Washington Hospital Center said in a statement released by the senator's office. “He will remain ... overnight for observation, and will be released in the morning.” The statement said the 76-year-old senator “is awake, talking with family and friends, and feeling well.” A spokeswoman at the Washington Hospital Center said the Massachusetts Democrat was awake and answering questions when he arrived and was able to receive a phone call from Obama. His wife Vicki and son, Rep. Patrick Kennedy, a Democrat, were with him. A few hours later, Sen. John Kerry, a Democrat, visited Kennedy, whom he said would remain overnight at the hospital. “He's laughing and joking right now. He's got all his Irish dander up,” he said.