Dr. John C. Marshall Honored for Influential Endocrinology Research

Dr. John C. Marshall recognized for clinical research in reproductive biology.

By Melissa Maki
John Marshall

John Marshall
Photo by Melissa Maki

Dr. John C. Marshall, director of the University of Virginia’s Center for Research in Reproduction, recently received the 2008 Clinical Investigator Award Lecture from The Endocrine Society. 

The Clinical Investigator Award Lecture is presented each year to an internationally recognized researcher who has made significant contributions to the pathogenesis, pathophysiology, and therapy of endocrine diseases.  This honor is one of 11 Laureate Awards presented annually to the world’s foremost endocrinologists.  It consists of an honorarium as well as the opportunity to give a plenary lecture.  Marshall was honored in June at ENDO 08, the 90th Annual Meeting of The Endocrine Society, in San Francisco.

Marshall’s recent studies have revolutionized the way that the medical community thinks about polycystic ovarian syndrome (PCOS).  PCOS is a disorder that afflicts some 1 in 12 women of childbearing age in the U.S.  Women with PCOS have enlarged ovaries that produce too much male hormone—or testosterone, which can disrupt the menstrual cycle and cause infertility as well as more serious complications such as heart disease.

Marshall studies the messages that come to the ovary from the brain.  In a normal female the brain sends a signal to the pituitary gland through a hormone called gonadotropin-releasing hormone.  The speed at which this signaling occurs determines whether the pituitary gland makes either Luteinizing hormone (LH) or Follicle-stimulating hormone (FSH)—the two hormones that control the ovary.  In women with PCOS, there is an imbalance of hormones—the LH message to the ovary being greater—which results in the ovary producing too much male hormone.

Through his research, Marshall established a link between obesity in young girls and this imbalance. “Normally you don’t think of the ovary as working that much in young girls,” says Marshall.  “But in truth, if they are obese, their insulin levels go up.  And then the insulin makes the ovary produce too much male hormone…The male hormone then changes the way the set points in the brain evolve as they go through puberty.  And then they end up with a system where by mid-puberty they are sending the wrong signal to the ovaries.”

Marshall’s work has demonstrated that about half of obese girls end up with this imbalance.  Since the National Institutes of Health (NIH) has determined that one in five girls today are obese, this is an alarming statistic.  “The long-term risks of PCOS are that it appears to make all the things that we know that are bad about being overweight and heavy that much worse,” says Marshall.  “There’s an increased risk of diabetes and an increased risk of metabolic syndrome, and those lead to an increased risk of heart disease.”

Marshall has been leading U.Va.’s Center for Research in Reproduction since 1996.  The center conducts both basic and clinical research in the area of reproductive biology in an attempt to understand the mechanisms of diseases at their cellular level so that this information can be readily translated into therapy that will benefit patients.  “What we try to do is take a lot of the technical advances that have been undoubtedly made and apply them to people as quickly as possible,” says Marshall.