Pentti K. “Finn” Siiteri, MD, PhD (Hon)

Pentti K. Siiteri

February 24, 2012

Dr. Pentti “Finn” Siiteri, a distinguished steroid biochemist and reproductive endocrine scientist died on Friday, February 24, 2012 in Sonoma, CA. He was an Honorary Fellow of this society. During the course of his long and storied career he made influential discoveries in a wide range of fields. His analytical work led to purification of commercially available streptokinase, but he is best remembered for his seminal studies of placental steroidogenesis, and the role of steroids and steroid hormone receptors in the genesis of breast, endometrial and prostate cancer. He also explored the role of protein and steroid hormones in altering maternal immune responses. He helped describe the fetal zone of the fetal adrenal as the major source of dehydroepiandrosterone sulfate (DHAS) production. His work with Norman Gant and Paul MacDonald greatly advanced our understanding of placental dysfunction in eclampsia.

Dr. Siiteri obtained his PhD under the legendary steroid biochemist, Dr. Seymour Lieberman, in the Department of Biochemistry at the College of Physicians and Surgeons, Columbia University. It was in Lieberman's lab that he met Paul MacDonald. By the end of his career he had amassed 124 peer review publications, many in high impact journals. He had a long record of NIH funding and served as chair of the Endocrine study section. Finn was a member and served leadership roles in the Endocrine Society, the Society for Gynecologic Investigation, and the Society for the Study of Reproduction. He was a recipient of the Order of the Lion of Finland, the highest civilian award granted by the President of Finland. He lived a long and accomplished life, and is survived by his wife of 62 years, Helen A. Siiteri, children Jon Everett (Rebecca), Eric Howard (Christine Luxen), Christian Martin (Darcie), Katherine Marie, and by 4 grandchildren; Jordan, Matthias, Parker and Leena Siiteri.

Dr. E. Aubrey Thompson, Professor of Cancer Biology at the Mayo Clinic Comprehensive Cancer Center was Finn Siiteri’s first graduate student, joining his laboratory in 1970, shortly after Finn and Paul MacDonald moved from Columbia to Southwestern Medical School. He was kind enough to share his reflections of his former mentor:

Perhaps the most telling tribute I can make to Finn Siiteri is the fact that I have told every graduate student with whom I have interacted, both in my laboratory and otherwise, that if you choose the right mentor, then being a graduate student is the best job in the world. That was certainly my experience. When I joined Finn’s group, he and Paul MacDonald were collaborating on a series of very exciting studies designed to study steroid hormone metabolism during pregnancy. These studies exemplify one of Finn’s most prominent characteristics: although trained as a synthetic organic chemist, he was devoted to the concept that has subsequently come to be known as “translational research”, but to Finn it was simply physiology; and physiology was all that really mattered in the long run.

Working with Thompson, the pair studied the mechanism of human placental aromatase activity accounting for the conversion of androstenedione to estrone. Thompson noted that “Finn was at heart an organic chemist, and the tritiated water reaction that he personally created remains a standard tool in the study of aromatase to this day. The elucidation of the role of cytochrome P450 in aromatization represents another major contribution that derived from those studies…” Thompson reflected on Finn’s larger than life personality observing that “Many perceived Finn to be an iconoclast, an argumentative skeptic; and perhaps there is some basis for this perception. But I saw him otherwise, as a man who was unswervingly committed to rigorous, well-controlled experimentation and intolerant of over-interpretation or disinclination to consider alternative hypotheses.”

Thompson described Dr. Siiteri’s chief characteristics as loyalty and devotion to his family (both personal and professional), experimental rigor, conservative interpretation of data, and consideration of alternative hypotheses. “He was a strong proponent of teamwork, particularly as it applied to collaboration between basic and clinical investigators. I have tried to adhere to these concepts and to teach them to my students and fellows, and I suppose that these precepts may be Finn’s most important legacy to me and my students. He was always a bit bigger than life to me, and many others. He had an indomitable love of life, and his passing does not sadden me; but there were few like him and his loss diminishes us all to a significant extent. Et lux aeterna lucient eis—Finn Siiteri, 2012.”

Submitted by Dr. Charles J. Lockwood

(My deepest thanks to Dr. E. Aubrey Thompson for sharing his reflections on Dr. Siiteri)

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