STOCKHOLM, Sweden--American researchers Gertrude Elion and George H. Hitchings and Sir James W. Black of Great Britain won the 1988 Nobel Prize in medicine yesterday for their discoveries leading to a series of new drugs.

The Nobel Assembly of the Karolinska Institute, which awards the prize, said Black developed a drug called propranolol in 1964 used in the treatment of heart disease. The work of Elion and Hitchings, who have collaborated since 1945, led to a series of drugs for the treatment of cancer.

The Americans' research also led to the development of drugs for the treatment of leukemia and malaria and to the creation of medicines designed to fight the rejection of transplanted organs, the awarding committee said.

Black, 64, works at King's College Hospital Medical School at the University of London. He received a Ch.B., or a bachelor of surgery, and an M.B., or a bachelor of medicine, from University of St. Andrews in Scotland.

Elion, 70, a New York City native, and Hitchings, 83, born in Hoquiam, Wash., are affiliated with Wellcome Research Laboratories in Research Triangle Park, N.C.

The institute cited the three researchers "for their discoveries of important principles for drug treatment."

It said Black "realized the great pharmacotherapeutic potential of receptor-blocking drugs."

In 1972, he discovered a group of histamine receptors, a finding that led to the development of the drug cimetidine. The drug introduced "a new principle in the treatment of peptic ulcer," said the institute's announcement.

Receptors are specific places to which drugs and natural substances attach themselves to produce their effects.

Discoveries by Elion and Hitchings led to drugs that stop cancer cells from reproducing their genetic material, thereby hindering growth of the cancer, the announcement said.

Their "research philosophy has formed the basis for development of new drugs against a variety of diseases," it said.

The most recent breakthrough in applying their research cited by the institute came in 1977, when the first effective drug was developed for treating herpes virus infections.

The three winners will share a cash award of 2.5 million kronor, or about $390,000, which they will receive at an awards ceremony Dec. 10.

The prize was approved by a majority vote of the institute's 50-member Nobel Assembly on the recommendation of a five-member committee which studied hundreds of research briefs over the last year. Normally about 250 researchers are nominated for the prize each year.