Dioxin causes reproductive system defects

[Carolyn Chase <cdchase@qualcomm.com>]

  University of Maryland at Baltimore
  2-Aug-97
  
              Endocrine disrupters: Dioxin causes reproductive system defects
  
  Library: MED
  Keywords: DIOXIN FEMALE REPRODUCTIVE DEFECT ENDOCRINE DISRUPTER
  REPRODUCTION DEVELOPMENT
  Description: A toxic chemical that lurks in the environment for years
  causes a vaginal defect
  in unborn rats, reproductive biologists from the University of Maryland
  School of Medicine
  have found.
  729241
  
  
  EMBARGOED UNTIL AUGUST 5, 1997
  
  Contact:
  Jennifer Donovan
  410-706-7946
  JenniferD@oia-2.ab.umd.edu
  
  Endocrine Disrupters
  DIOXIN CAUSES REPRODUCTIVE SYSTEM DEFECTS
  
  A toxic chemical that lurks in the environment for years causes a vaginal
  defect in unborn rats.
  The abnormality is a web of tissue that partially obstructs the vaginal
  opening and may impair
  the rats' ability to reproduce.
  
  "If dioxin does that, what else might it be doing? Is it affecting the
  reproductive health of
  human beings?" said Dr. Mary Dienhart, a reproductive biologist from the
  University of
  Maryland School of Medicine. She presented research findings on August 5 to
  the Society for
  the Study of Reproduction annual meeting in Portland, Oregon.
  
  Dienhart is a member of a research team headed by Dr. Anne N. Hirshfield,
  professor of
  anatomy and neurobiology at the UM medical school. Working with Dr. Richard
  Peterson at the
  University of Wisconsin, they examined the offspring of pregnant laboratory
  rodents exposed to
  single doses of dioxin, a highly toxic chlorinated byproduct from the
  bleaching of pulp to make
  paper. It also is produced by many incineration processes. The dose was
  1,000 times that of the
  typical environmental exposure of people in industrialized countries.
  
  Within less than a week after exposure, three out of four of the unborn
  female rats had
  developed the vaginal defect. The toxic chemical, known to be a disrupter
  of the endocrine
  system, persists in the environment,. It enters the food chain and is
  accumulated in livestock and
  fish, where it is stored in fat, which is the major route of human
  exposure. Although the
  mechanism is not known, dioxin is known to cause changes in hormones and
  growth factors that
  could have profound effects on the growth and development of the
  reproductive system.
  "Hormones are signaling molecules; they tell genes when to turn on and turn
  off," Dienhart
  explained. "Development is a complex genetic program. If you interfere with
  it anywhere along
  the line, you could cause an entire cascade of events that could adversely
  affect reproductive
  health." Next, the Maryland researchers want to look at the molecular
  mechanism underlying
  the development of the vaginal defect, to determine if it is interfering
  with cell formation or
  programmed cell death. Their study of the developmental effects of dioxin
  was funded in part
  by the Bressler Foundation and the National Institutes of Health.
  
  ###