Environmental Exposures and Early Onset of Puberty

November 16, 2010
1:00 pm US Eastern Time

Audio

Over the last several decades, the age of puberty in industrial countries has fallen, particularly in female children. A variety of reasons have been proposed to explain this trend. Recent research supports the idea that environmental exposures may be linked to an earlier onset of puberty.HE Fertility and Reproductive Health Working Group hosted a conversation with researchers in early puberty to learn more and discuss the issues.

Featured Speakers

Heather Patisaul is an Assistant Professor of biology at North Carolina State University who specializes in neuroendocrinology, sexual differentiation within the brain, and endocrine-disruption research. She also served as a science communication fellow for Environmental Health News in 2009 and received an Outstanding New Environmental Scientist Award from the National Institute of Environmental Health Sciences (NIEHS) in 2007 which helps fund her ongoing research. Dr. Patisaul discussed reproductive health effects on female rats that have been exposed to bisphenol-A (BPA) or the soy phytoestrogen genistein at levels equivalent to or below the dose that has been thought not to produce any adverse effects.

Mari Golub is an Adjunct Professor in the Department of Environmental Toxicology and conducts research within the California National Primate Research Center at the University of California, Davis. She specializes in developmental neurotoxicology, emphasizing behavioral assessment of brain function. Dr. Golub also conducts risk assessment activities through an appointment at the California Environmental Protection Agency. She presented her findings from a study comparing the consequences of treatment with two estrogenic agents, methoxychlor (MXC) and diethylstilbestrol (DES) on female rhesus monkeys in the peripubertal period.

Michele Marcus is Professor of Epidemiology and Environmental Health at the Rollins School of Public Health at Emory University and and is Co-Director of the Pediatric Environmental Health Specialty Unit at Emory University. She is currently Principal Investigator of several environmental health research projects funded by the National Institutes of Health and the CDC. Dr. Marcus presented her research on the health effects of exposure to Brominated Flame Retardants among a farming community in Michigan. Thirty years ago an industrial accident resulted in the contamination of livestock feed with Brominated Flame Retardants and the distribution of contaminated meat and dairy products throughout the state.

The call was moderated by Karin Russ, CHE Fertility Coordinator, and recorded.

Dr. Mari Golub's presentation slides

Additional Resources

Public Health Implications of Altered Puberty Timing, Pediatrics, 2008.
Mari S. Golub, PhDa,b, Gwen W. Collman, PhDc, Paul M.D. Foster, PhDd, Carole A. Kimmel, PhDe, Ewa Rajpert-De Meyts, MD, PhDf, Edward O. Reiter, MDg, Richard M. Sharpe, PhDh, Niels E. Skakkebaek, MD, DMScf, Jorma Toppari, MD, PhDi
From the abstract: Changes in puberty timing have implications for the treatment of individual children, for the risk of later adult disease, and for chemical testing and risk assessment for the population. Children with early puberty are at a risk for accelerated skeletal maturation and short adult height, early sexual debut, potential sexual abuse, and psychosocial difficulties.

Effects of Exogenous Estrogenic Agents on Pubertal Growth and Reproductive System Maturation in Female Rhesus Monkeys, Toxicological Sciences, 2003.
Mari S. Golub, Casey E. Hogrefe, Stacey L. Germann, Bill L. Lasley, Kala Natarajan, Alice F. Tarantal
From the abstract: Concern has been raised that environmental contaminants with estrogenic properties can alter normal sexual maturation. Monkeys, like humans, undergo a long and complex period of development during adolescence, which makes them important models for understanding exogenous estrogen effects during this period.

Neonatal bisphenol-a exposure alters rat reproductive development and ovarian morphology without impairing activation of gonadotropin-releasing hormone neurons. Adewale, Heather B. Jefferson, Wendy N. Newbold, Retha R. Patisaul, Heather B. (2009). Biology of Reproduction. 81(4):690-9, 2009 Oct.
From the abstract: Developmental exposure to endocrine-disrupting compounds is hypothesized to adversely affect female reproductive physiology by interfering with the organization of the hypothalamic-pituitary-gonadal axis. Here, we compared the effects of neonatal exposure to two environmentally relevant doses of the plastics component bisphenol-A (BPA; 50 microg/kg and 50 mg/kg) with the ESR1 (formerly known as ERalpha)-selective agonist 4,4',4''-(4-propyl-[(1)H]pyrazole-1,3,5-triyl)trisphenol (PPT; 1 mg/kg) on the development of the female rat hypothalamus and ovary.

Impact of neonatal exposure to the ERalpha agonist PPT, bisphenol-A or phytoestrogens on hypothalamic kisspeptin fiber density in male and female rats. Patisaul, Heather B. Todd, Karina L. Mickens, Jillian A. Adewale, Heather B. (2009). Patisaul HB. Todd KL. Mickens JA. Adewale HB.
Neurotoxicology. 30(3):350-7, 2009 May.
From the abstract: Neonatal exposure to endocrine disrupting compounds (EDCs) can impair reproductive physiology, but the specific mechanisms by which this occurs remain largely unknown. Growing evidence suggests that kisspeptin (KISS) neurons play a significant role in the regulation of pubertal onset and ovulation, therefore disruption of KISS signaling could be a mechanism by which EDCs impair reproductive maturation and function.

Neonatal genistein or bisphenol-A exposure alters sexual differentiation of the AVPV. Patisaul, Heather B. Fortino, Anne E. Polston, Eva K. (2006). Patisaul HB. Fortino AE. Polston EK. Neurotoxicology & Teratology. 28(1):111-8, 2006 Jan-Feb.
From the abstract: There is growing concern that naturally occurring and chemically manufactured endocrine-active compounds (EACs) may disrupt hormone-dependent events during central nervous system development. We examined whether postnatal exposure to the phytoestrogen genistein (GEN) or the plastics component bisphenol-A (BIS) affected sexual differentiation of the anteroventral periventricular nucleus of the hypothalamus (AVPV) in rats.

NIEHS: An independent panel of 14 scientists was convened in March 2006 by the Center for the Evaluation of Risks to Human Reproduction (CERHR) (31) to evaluate whether genistein or soy formula is hazardous to human development or reproduction. View the final report. The report found that: “There are no human data available on developmental or reproductive toxicity of purified genistein. Available experimental data are sufficient to conclude that purified genistein can produce reproductive and/or developmental toxicity in rats and mice.”

Genetic variation in LIN28B is associated with the timing of puberty. Ong KK. Elks CE. Li S. Zhao JH. Luan J. Andersen LB. Bingham SA. Brage S. Smith GD. Ekelund U. Gillson CJ. Glaser B. Golding J. Hardy R. Khaw KT. Kuh D. Luben R. Marcus M. McGeehin MA. Ness AR. Northstone K. Ring SM. Rubin C. Sims MA. Song K. Strachan DP. Vollenweider P. Waeber G. Waterworth DM. Wong A. Deloukas P. Barroso I. Mooser V. Loos RJ. Wareham NJ. (2009) Nature Genetics. 41(6):729-33, 2009 Jun.