The influence of lead ions on uterine activity in the rat.

Spontaneous uterine activity and reactivity to oxytocin, naproxen and PGF2 alpha were studied in vitro in 80 rats, which for 2-8 weeks had been exposed to different concentrations and combinations of Pb2+, Zn2+ and Cu2+ in their water supply or had been given clean water for control. In rats given only Pb2+ in concentrations of 1000 and 500 ppm for 6 weeks the uterine activity was significantly increased, whereas in groups given the other ions alone, or Pb2+ for 6 weeks followed by 2 weeks of clean water or Zn2+ or Cu2+ no change was observed. The responses to the oxytocin, naproxen and PGF2 alpha did not differ. These results suggest that contamination with lead ions might be one of the etiological factors involved in conditions with increased uterine activity.