Doctors say a drug taken by transplant recipients to prevent organ rejection will be tested on diabetics to see if it helps them fight the disease.

The drug, FK-506, already has shown promise in reversing the effects of some types of skin diseases, leading researchers to study whether it will halt the onset of a related type of diabetes, said Dr. Thomas Starzl.Starzl heads the University of Pittsburgh's transplant program, where about 800 patients since February 1989 have taken the drug to prevent their white blood cells from rejecting donor organs.

He said Wednesday that the drug also shows promise in treating auto-immune diseases, in which the body's white cells destroy healthy cells.

The U.S. Food and Drug Administration has approved a two-year test of the drug on 60 Type 1 diabetes patients, Starzl said.

FK-506 has already reversed the effects of psoriasis, a skin disease that creates unsightly lesions, in all six patients who took it, Starzl said.

The drug also reversed the effects of pyoderma gangrenosum, a rare skin ulcer, in six of seven patients, he said.

"We're seeing some very dramatic recoveries," said Starzl who performed the world's first successful human liver transplant in 1967.

He said researchers want to move ahead quickly with the tests on people with Type I diabetes, in which a person's white cells destroy their pancreas' insulin-producing factories, requiring the person to take insulin shots to survive.

"We are anxious to get the information out that there is something that could switch off this disease," he told reporters.

At least 11 million Americans suffer from Type 1 diabetes, which can cause blindness and kidney failure. Its symptoms are excessive thirst, frequent urination, rapid weight loss and blurred vision.

Transplant patients using the drug have displayed such side effects as dizziness and excessive dreaming, said Dr. Patricia Carroll of the university's medical school. But she said side effects haven't shown up in people who have taken the drug but who have not undergone transplants.