Oxytocin-induced parturition in copper-deficient guinea pigs.

Dietary copper-deficient guinea pig dams (0.8 microgram Cu/g diet) were administered oxytocin to induce delivery of pups, whereas dietary copper-sufficient guinea pig dams (5.8 micrograms Cu/g diet) had uneventful deliveries with 79% surviving pups. The copper-deficient dams carried the fully-formed fetuses to term but did not go into labor unless 0.5 to 6.2 U oxytocin was administered (i.m.). Birth of live pups from copper-deficient dams increased from 28% overall, to 50% if oxytocin was administered in a timely manner. Many pups died of internal hemorrhages probably the result of defective connective tissue crosslinks requiring copper as a co-factor for lysyl oxidase activity. Dietary copper deficiency may be a factor in depressed parturition in the copper-deficient guinea pig dam that responds to administration of exogenous oxytocin for delivery of pups.