EFFECTS OF CADMIUM ON MYOMETRIAL ACTIVITY OF THE NONPREGNANT HUMAN - INTERACTIONS WITH CALCIUM AND OXYTOCIN

With respect to recent reports suggesting an involvement of cadmium in preterm labor, the effects of this ion on the activity of myometrial strips from term pregnant women were examined, The interactions of cad mium with calcium and oxytocin on myometrial activity were also studie d, Cadmium alone inhibited spontaneous contractile activity already in a concentration of 10(-9) M and in 10(-3) M myometrial contractions w ere almost completely abolished. Responses to Ca2+ and oxytocin were s ignificantly increased by exposure to cadmium in low concentration (10 (-9) M-10(-8) M), whereas higher concentration of Cd2+ had inhibitory action. These results suggest that cadmium not only blocks Ca2+ channe ls in the human myometrium, but also interferes with intracellular mec hanisms involved in excitation - contraction coupling. The increased r esponses to Ca2+ and oxytocin in the presence of low amounts of Cd2+ s upport a role of cadmium in mechanisms of preterm labor.