Whole-body autoradiography of 63Ni in mice throughout gestation

Whole-body autoradiography was used to study nickel uptake and retention in mice throughout gestation. After an intraperitoneal injection of 50 muCi 63NiCl2 into a 16-day-pregnant mouse, nickel appeared rapidly in connective tissues. Prominent sites of radioactivity 72 h after injection included the visceral yolk sac, lung, gastrointestinal tract and kidney. Nickel crossed the placental barriers throughout gestation, i.e. the visceral yolk sac during early gestation, the visceral yolk sac and chorioallantoic placenta during late gestation. A marked uptake of nickel was seen already in the 5- and 6-day embryo. Fetal accumulation of nickel took place up to 16 days gestation. Whereas nickel was distributed throughout the early embryo, distribution became more differentiated with increasing gestation, imitating that in the mother. Penetration of nickel into the mouse conceptus makes possible a similar ability in the human conceptus.