Once upon a time, somewhere on the banks of the Nile . . ." begins DMS biochemist Lee Witters, M.D. He's just delivered a one-hour overview of diabetes to an undergraduate endocrinology class and has now instructed the students to put down their pens and pencils and simply listen to a story. He explains that he's been coached by his wife, a professional storyteller, as to how all stories should begin ("Once upon a time . . .") and end.

For the next 40 minutes, Witters tells a tale about the history of diabetes, from early Egyptian and Greek descriptions of the disease to the discovery of insulin at the University of Toronto in the 1920s. He shows the class historical photographs and centuries-old scientific papers, as well as a clip from a Canadian film about the discovery of insulin. And he weaves in interesting, human details—the kind that make scientific discoveries fascinating but that often get lost in a sterile, factual recounting.

All eyes are fixed on Witters. The students aren't doodling, filling in crossword puzzles, or completing homework for other classes the way they sometimes do during lectures. Although Witters runs a few minutes over the scheduled end of the period, the students remain riveted in their seats. There isn't even the usual rustle of papers and book bags. Finally, Witters wraps up the tale. With the discovery of insulin, he concludes, "a diabetic could live happily ever after."

Witters, the Eugene W. Leonard 1921 Professor of Medicine and of Biochemistry at Dartmouth Medical School, never expected to devote so much time to teaching undergraduates—or to be so good at it. (He teaches three undergraduate courses and also lectures in a few Medical School courses.) He spent much of his career as a bench researcher and clinician, earning a reputation as a leader in his field at Harvard from 1973 to 1984 and at Dartmouth since 1984. But teaching has "really changed me over the last 10 years," says Witters. "It's become what I do." And by all accounts he does it well. He's received numerous teaching awards at the College and DMS, including Faculty Advisor of the Year, Teacher of the Year in the Basic Sciences, Professor of the Year, and Profiles in Excellence Teaching Award.

"Lee is a natural teacher," says Christina Ullrich, M.D., a 1994 Dartmouth College graduate who worked in Witters's lab for two years before going on to Harvard Medical School. Ullrich is now a fellow in pediatric hematology-oncology and in

pediatric palliative care at Children's Hospital of Boston. She says Witters made "enzymatic pathways or hormonal feedback loops . . . not just abstractions but phenomena that were relevant to our everyday lives."

And "he has so much patience," says another former student, Hiram Shaish, a DC '05 who plans to attend medical school. Shaish recalls Witters repeating concepts over and over in class, and at office hours never admonishing students, "Didn't you come to class?"

As head of the College's Nathan Smith Premedical Society, Witters enjoys mentoring as well as teaching. He has helped many undergraduates figure out whether to pursue a career in medicine. "We had more than a few 'sorting out Patrick's life' chats," says Patrick Ward, a DC '05 who is finishing a year-long research fellowship at Cambridge University in England. Next fall, Ward will begin an M.D.-Ph.D. program at the University of Pennsylvania. He has a special appreciation for how devoted Witters is to his students. Ward not only took Witters's courses but also worked in his lab for three years.

"Working in Lee's lab gave me the chance to really see how much time he puts into revising his courses each year, which is on the order of weeks and months per class—before [they] even begin," says Ward. "Add on top of that the countless office hours that Lee makes available

during term-time to his undergraduate students, [and] it is a true wonder how he ever gets anything else done, let alone put in the time necessary to run a lab, fulfill his Medical School teaching duties, run the premed society, start a human biology program, and do half a dozen other things."

Ward, a long-distance runner, was initially drawn to Witters's lab because it focuses on the biological basis of endurance at the cellular level. The lab studies the enzyme AMP-activated protein kinase (AMPK), which regulates cell metabolism and energy levels and plays an important role in cancer, appetite control, and type II diabetes.

Witters's lab was one of the first to focus on AMPK, says Laurie Goodyear, Ph.D., an investigator at the Joslin Diabetes Center in Boston, but worldwide research on the enzyme has "just taken off in the last five years or so." Goodyear, who collaborates with Witters on AMPK, describes him as "a really good scientist and thinker . . . laid back but intense." And, she adds affectionately, "a character."

Witters sports a wiry ponytail, dresses casually, and has a keen sense of humor. He and his wife live in a log-cabin home on 100 acres in Norwich, Vt. It's known as the "Witters homestead" to the dozens of students who come out there for