While studying the effect of post-menopausal dietary soy consumption on estrogen metabolism in cynomolgus monkeys, Latanya M. Scott, Ph.D., discovered that monkeys who had been given birth control earlier in life had a reduced amount of estrogen excreted in their urine. The research was done in collaboration with Xia Xu, Ph.D., and Timothy Veenstra, Ph.D. at Science Applications International Corporation-Frederick, Inc., in Frederick, Md., who have developed novel methods for analysis of urinary estrogens.
The discovery was particularly noteworthy because it was found three years after oral contraceptive treatment was stopped, roughly the equivalent of a decade of life in a human.
While researchers have known for many years that past oral contraceptive use significantly lowers the risk of ovarian and uterine cancers later in life, this new observation in monkeys may shed light on the mechanism behind the cancer-protective effect of the treatment. Past oral contraceptive use appears to result in a long-term change in the way the monkeys' bodies process hormones. While researchers don't yet understand the precise mechanism by which hormone levels are being affected, they do know that both the level of estrogen in the blood and the amount of estrogen being excreted in urine are lowered with past oral contraceptive use, which may mean that the oral contraceptive use is somehow leading to a diminished synthesis of estrogen.
The study appears in this month's issue of Cancer Epidemiology, Biomarkers and Prevention.
"Hormone exposure has long been known to be important in cancer risk," said J. Mark Cline, D.V.M., Ph.D., and senior researcher on the project. "These effects are robust, and we believe this discovery could be translated fairly quickly into a study in women. If our results are confirmed to also occur in women, they could change the way we look at oral contraceptives and cancer risk," added Cline, a professor of pathology and comparative medicine.
With funding from the National Institutes of Health, researchers began with 181 premenopausal cynomolgus monkeys and followed them for seven years in a study designed to look at hormone effects on many aspects of female health.
Half of the monkeys were given a birth control treatment of triphasic estrogen and progestin, marketed by Wyeth Pharmaceuticals as TriphasilTM, for 26 months. At the end of the premenopausal phase of the study, the animals underwent surgery to have their ovaries removed, making them surgically menopausal.
The postmenopausal monkeys were then divided into three dietary intervention groups to evaluate the effects of soy on hormone metabolism.
Urine samples were collected from each monkey during the 35th and 36th months of the postmenopausal phase of the study and frozen for subsequent analysis of metabolite concentrations.
Lab results showed that the premenopausal use of oral contraceptives resulted in significantly lower levels of most estrogen metabolites three years after surgical menopause. Among the most abundant metabolites, percent changes ranged from a 25 percent reduction in E1 to a 50 percent reduction in 2OHE1 with oral contraceptive administration. Postmenopausal dietary isoflavones induced fewer significant effects on postmenopausal estrogen metabolite concentrations.
"The magnitude and persistence of oral contraceptive effect really surprised us," said Cline, a diplomate of the American College of Veterinary Pathologists. "It tells us that there may be a new and potentially strong cancer-protective mechanism at work. This could open new doors of inquiry in the field."
Jessica Guenzel | EurekAlert!
Laser activated gold pyramids could deliver drugs, DNA into cells without harm
24.03.2017 | Harvard John A. Paulson School of Engineering and Applied Sciences
What does congenital Zika syndrome look like?
24.03.2017 | University of California - San Diego
Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.
The results will be published on March 22 in the journal „Astronomy & Astrophysics“.
Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...
Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.
Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...
In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...
Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to simulate these confined natural conditions in artificial vesicles for the first time. As reported in the academic journal Small, the results are offering better insight into the development of nanoreactors and artificial organelles.
Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to...
20.03.2017 | Event News
14.03.2017 | Event News
07.03.2017 | Event News
24.03.2017 | Materials Sciences
24.03.2017 | Physics and Astronomy
24.03.2017 | Physics and Astronomy