Rarely do people in their 50s take up running events of 26.2 miles. And rarer, still, do they decide to run one while recovering from the difficult surgery needed to donate a kidney. I guess that makes Christina Pitts of Grosse Pointe Woods pretty rare.

After donating a kidney to her brother, Michael Pitts of Modesto, Calif., in March 1999, Pitts started running marathons to raise money for charitable causes, and to show the world just how active organ donors could be if they set their minds to it.

"I don't think I'd do marathons if it wasn't for raising money. It's just too arduous otherwise," said Pitts. "This keeps me going."

She raised $16,000 in her first two marathons, both for the American Diabetes Association: Kona in 2000 and DisneyWorld last January. I had started to do a story on her for the Detroit News after the Kona race, then took a full-time job for awhile - horrors! - that put most of my free- lancing on hold. When I quit my job earlier this year, I told her maybe we could revive the story.

Was she training for a third marathon? If so, maybe the Detroit News would be interested in a story. We met for a run and she said she'd be happy to do a third marathon, but wanted to go somewhere cool. What would I suggest?

I told her about Big Sur, St. George in Utah, the Avenue of the Giants through the California redwoods, and Lake Tahoe. Since it was July when we got together and Tahoe was in October - as we go to press, the marathon is a few days away, as you're reading this, it's history - Tahoe was out, or so it seemed.

But the Real McCoy was in.

You won't find the Real McCoy Marathon in listings for fall marathons, and Runner's World magazine has never heard of it. That's because to the rest of the world, it's known as the Tahoe Marathon in Lake Tahoe, but to Pitts it's a tribute to Cathy McCoy of Troy. McCoy, Pitts's golfing and Scrabble buddy, had been diagnosed with lung cancer in late May. When Pitts and I got together in July, she knew she wanted to do a marathon in McCoy's honor. Subsequent events - the word McCoy's cancer had spread, radiation and chemotherapy were being halted and she didn't have long to live - gave a special urgency to Pitts running for her friend.

McCoy, a sales rep for Enesco Group Inc., which manufactures the Precious Moments line of collectibles, was thrilled Pitts asked if she could run her next marathon in her honor, raising money for Gilda's Club in the process.

"Tears welled up in her eyes," said Pitts.

"I'm happy and kind of surprised that my little blip on the radar screen of life can be seen as interesting enough to share," said McCoy when I visited her in late August. "I hope I can do some good."

"This motivates me even more," said Pitts. "I have to do this for Cathy and other people who have cancer. I WILL do this. Her face will be in the mind movie I'll be playing during the marathon. I know I'll be in tears when I'm running.

"Every time Cathy sees me, she asks, 'How are we doing on donations?' I'm hugely sad because we were hoping she'd be able to go to Tahoe and be part of it," said Pitts in mid-September, with McCoy sinking fast. "I was hoping to wheel her at the Gilda's Walk Sept. 28, but now it looks like she won't be able to do that either."

Pitts, 55, who jokingly describes herself as "a recovering attorney," now owns a consulting firm. She also raised money through the Real McCoy for the Michigan Humane Society, Diabetes Association, National Association for Children of Alcoholics, and AIDS Partnership Michigan. "I've suffered tragic losses in my life," says Pitts. "This is a way for me to make someone else's life better or their family happier. If they know someone else out there cares, even if I'm a stranger, then I've done something.

"There's someone in Africa who has AIDS who didn't ask for it. There are animals who are suffering. There are people with cancer who need Gilda's Club. You make a difference one step at a time." Or in the thousands of steps it takes to go 26.2 miles.

Pitts had run local 5Ks and 10Ks, but never a marathon until Kona. In June 1999, someone told her about Team Diabetes. Participants get coaching advice, people to train with and a free trip to a destination marathon, provided they hit fund-raising goals. "I knew I wanted to do more as a volunteer to fight diabetes," she remembered, "and thought, 'That's it!"

Her brother, Michael, had a number of post-operative complications, and his diabetes resulted in the amputation of his right leg below the knee. Since then, he's been fitted with a prosthetic that allows him to walk and drive, and is back to work as a lumber sales rep. He even did something recently that he once thought would be impossible: fly back to the Detroit area for a family reunion.

"The transplant from Christine gave me the opportunity to survive," said Michael. "There was a five-year estimated wait for a donor if she hadn't been a match, and I wouldn't have survived that long on dialysis. I'm one of the lucky ones.

"I realize the courage, commitment and love that goes with how I got this kidney. Christine went through more pain than I did and her recovery time was longer," said Michael, referring to the surgical trauma a kidney-donor undergoes, including extensive tissue cutting and breaking of a rib.

Long runs used to take Christine two hours or more. Now they take an hour longer. But it hasn't slowed her ambitions.

"I take out flyers and stop to chat with people along the way," she said. "I tell them I run marathons for charity and that breaks the ice. I did 13 miles Wednesday and it took me an extra 55 minutes with all the stops along the way. I passed out a handful of flyers. One man took one and said I should run for Alzheimer's, because that's what he has. It's a nice way to meet people."

Pitts's Real McCoy Marathon is over, but you can still donate in Cathy's honor by doing this: Send a check, and write "Christina: Ribbons of Hope" in the memo line, to one of these charities:

* AIDS Partnership Michigan, 2751 E. Jefferson, Suite 301, Detroit, MI 48207.

* American Diabetes Association, 30300 Telegraph, Suite 117, Bingham Farms, MI 48025.

* Gilda's Club Metro Detroit, 3517 Rochester Road, Royal Oak, MI 48073.

* National Association for Children of Alcoholics, 11426 Rockville Pike, Suite 100, Rockville, MD 29852.

*Michigan Humane Society, 26711 Northwestern Highway, Suite 175, Southfield, MI 48034. MR