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Hormonal Link Between Nutrition and Reproduction Discovered
FOR IMMEDIATE RELEASE -- A collaborative project between ZymoGenetics, Inc. and UW researchers, including a 17-year-old undergraduate, discovers a hormonal link between nutrition and reproduction.The discovery, published in the July issue of Endocrinology, provides an explanation for how the body's reproductive system determines whether there are sufficient energy stores to support reproductive processes.
Among the researchers is UW undergraduate Ilona Barash, 17, who entered the university at 13 years old under the early entrance program. Barash, the first author of the paper, is a senior this year working toward a double major in German and biochemistry.
"I was always interested in science in general," she said. Barash has been involved in lab research for the past year, and plans to put the experience toward an MD.-Ph.D. once she receives her undergraduate degree.
The early entrance program admits 16 students no older than 14 by Aug. 31 of the year they begin at the UW. The students take math, physics, history and English in a classroom in Guthrie Hall Annex 2 during their first two quarters. During their third quarter, the students replace physics with a regular university course.
At the end of the first transitional year, the students enter the UW as freshmen. The UW does not in fact require a high school diploma for admission.
Barash's contributions were made in the lab of lead researcher Dr. Robert A. Steiner, UW School of Medicine professor of obstetrics and gynecology, physiology and biophysics, and zoology. The research, conducted in mice, shows that leptin, a hormonal product secreted by fat cells, serves as a metabolic signal to the reproductive system, Steiner said.
"People have known for thousands of years there is some connection between fertility and nutrition, but exactly how this connection is physiologically forged has not been understood," he said.
The Endocrinology article explains that leptin connects reproduction and body fat by communicating to the reproductive system that sufficient fat stores are available to meet the demands of reproduction.
Barash said the implications of the research on leptin for humans are still unclear, but scientists have a better understanding and new studies are underway to answer those questions. As part of her undergraduate thesis research in Steiners laboratory, Barash is now exploring leptin's possible role in timing the onset of puberty.
University of Michigan reproductive science professor Dr. Douglas Foster, a noted expert in the field of nutrition and reproduction, said the Endocrinology article will add fuel to the fire in this area of research. "It seems appalling in these days of sophisticated molecular biology that we have embarrassingly little understanding of how the brain knows if the body is well or poorly fed," he said.
Fertility in mammals requires adequate nutrition and metabolic fuel reserves. Previous research has shown that people with anorexia and high performance athletes, particularly those who are very thin, have severely impaired reproductive systems. Researchers suggest that metabolic stresses such as food restriction and highly strenuous exercise are signaled to the reproductive system via low circulating levels of leptin, indicating the resources necessary for successful reproduction are not available. When the persons nutritional status improves, his or her leptin levels and metabolism increase, activating the reproductive system and restoring fertility.
Although leptin has been patented by a major medical pharmaceutical corporation and is not commercially available, ZymoGenetics, Inc. of Seattle, which has the technical capabilities to clone and synthesize leptin, provided the leptin and collaborated with UW researchers. "It would have taken a lab at the university quite some time to make it," said ZymoGenetics scientist Dr. D. Scott Weigle.
Weigle, an associate professor of medicine on sabbatical leave from the School of Medicines Division of Endocrinology, works at ZymoGenetics on projects related to understanding obesity. He said it is important for people to know that fat makes it possible for humans to reproduce.
News Release