WASHINGTON -- A Major League Baseball official urged Congress on Tuesday to regulate substances such as androstenedione, the over-the-counter supplement Mark McGwire used the year he broke the single-season home run mark.

Rob Manfred, baseball's executive vice president for labor relations, made the suggestion at a Senate hearing examining the use of steroids in baseball.

Donald M. Fehr, executive director of the Major League Baseball Players Association, agreed it might be time for Congress to look again at andro, which, like illegal steroids, helps the body create testosterone.

While the Players Association and baseball seemed close to agreeing on andro, they diverged sharply on whether players should be tested for steroids.

Baseball is under scrutiny after former National League MVP Ken Caminiti admitted using steroids and estimated that half of the sport's players do as well. Former American League MVP Jose Canseco said up to 85 percent took steroids. Both players declined invitations to testify Tuesday.

Sen. Byron Dorgan, D-N.D., who chaired the hearing of the Senate Commerce subcommittee on consumer affairs, said it was too soon to say whether Congress would follow up with legislation.

"It's a complicated topic," said Dorgan, whose former chief of staff, Lucy Calautti, is now baseball's lobbyist. "There are so many substances -- where does one start?"

Sen. John McCain, R-Ariz., noted that sales of andro skyrocketed after the 1998 revelation that McGwire was using the substance. The retired Cardinals' slugger, who hit 70 home runs that year, stopped taking the drug the following season, saying he was worried that kids would follow his lead.

"Like it or not, professional athletes serve as role models," McCain said. "That's more important than whether a group of highly paid athletes are using anabolic steroids."

The NBA, NFL, NCAA and Olympics all ban andro.

Frank Shorter, an Olympic marathon gold medalist who now chairs the U.S. Anti-Doping Agency, said andro was originally developed as part of the East German steroid program. He said a 12-year-old can now purchase it at a dietary supplement store.

While the Players Association and baseball seemed close to agreeing on andro, they diverged sharply on whether players should be tested for steroids.

Jerry Colangelo, who owns both baseball's Arizona Diamondbacks and the NBA's Phoenix Suns, noted that basketball has mandatory random tests for steroids.

"Such a step would be a necessary and fundamental step in the direction of ridding steroid use in Major League Baseball," said Colangelo. The NFL also tests for steroids.

But Fehr said the union believes testing players without cause would violate their privacy. He said that the players would work to come up with a solution as part of the collective bargaining process with the owners on a new contract.

"No one cares more about the game, the health of the players, than the players themselves," he said.

Said McCain: "The credibility of their performances ... is at stake here."

Fehr also serves as board member of the U.S. Olympic Committee, which tests athletes for steroids. Asked about that after the hearing, he said there was no connection between the two.

"I never participated in testing discussions at the USOC," he said.