Kelly Blair, who owns a gym in Pasadena, Texas, was the source of the substance, the New York Daily News reported Sunday.
Pettitte, who has admitted using HGH in 2004, told congressional attorneys that he received it from his father, Tom Pettitte, who has had serious health problems. In his deposition, Pettitte said his father got the drugs from a trainer at a gym where he worked out but did not identify the trainer.
The Daily News reported that Blair sold HGH and steroids to customers at 1-on-1 Elite Personal Fitness. Blair did not respond to the newspaper's requests for comment.
Pettitte and Blair attended nearby Deer Park High School, east of Houston, at the same time; Blair was a football and track star. Pettitte's wife's brother married Blair's sister.
Copyright 2008 The Associated Press. This story was not subject to the approval of Major League Baseball or its clubs.