David Baltimore, American Cancer Society Professor of Microbiology at the Massachusetts Institute of Technology, was named one of three recipients of the 1975 Nobel Prize in Medicine and Physiology yesterday.

Baltimore co-discovered reverse transcriptase--the enzyme which enables viruses with RNA to insert their genetic information into the host cell's genes--in 1970 with the other two prize winners announced yesterday.

Co-winners

Howard M. Tomin of the University of Wisconsin and Renato Delbecco of the British Imperial Cancer Research Fund were named with Baltimore as co-winners of the 1975 prize.

At a press conference yesterday, Baltimore said that "apart from drinking champagne, nothing much has happened out of the ordinary," since he learned of the award.

He said he has received no "battery of telegrams," but that there had been "a lot of calls from friends I haven't seen in a long time."

Sweet Sixteen

Baltimore said that he first became interested in biology in 1958, while he was attending Swarthmore College. Until that time, Baltimore said, "I think I heard it mentioned in high school when I was about sixteen."

Baltimore said it had been his curiosity about biology that had motivated his work. "Because cancer is such a terrible disease, it receives a greet deal of publicity. My motivations, however, were more biological than anything else," he said.

Shortly after the press conference, Baltimore received the official telegram from Stockholm informing him of the award. The brief message was a mere four lines long.