PLACENTAL COPPER TRANSPORT IN THE RAT .2. EFFECT OF MATERNAL COPPER DEFICIENCY

Copper (Cu) placental transport presents a steep downhill gradient fro m mother to fetus. This process could be altered by low-molecular-weig ht (LMW) ligands and maternal Cu deficiency. We compared the ratio of Cu transfer from dam-to-fetus in Cu-deficient (CuDf) and Cu-sufficient (CuSf) rats in the last day of gestation. Anaesthetized dams were iv injected 79 mu mol/kg (5 mg/kg) of either Cu acetate [Cu (Ac0)(2)]; Cu +L-histidine, 1 : 10, [Cu(His)(10)]; Cu-(glycyl-glycyl-L-histidine) [C u(GGH)], or saline. Dam and fetal blood, as well as placentae were obt ained at 0, 10, 20, 40 and 60 min. At time 0, CuDf dams had lower plas ma Cu than CuSf dams (8.3 +/- 1.2 versus 26.7 +/- 1.1 mu mol/l), but C uDf fetuses plasma Cu was unchanged. This resulted in a more favourabl e mean fetal : maternal plasma Cu ratio in the CuDf fetuses (0.61) tha n in the CuSf fetuses (0.21). Dam plasma Cu was unaffected by the chem ical form of Cu injected. In CuDf fetuses lower plasma Cu was observed with Cu(GGH) and Cu (His)(10) at 20 min than in the CuSf. In the pres ence of these LMW ligands CuDf placentae retained more Cu than those o f the CuSf group. CuDf was associated ultrastructurally with extensive lipid deposition in dam hepatocytes and, to a lesser extent, in CuDf fetal liver. These results indicate that in CuDf, LMW ligands increase placental uptake of Cu, without improving placenta-fetus transport. A lthough the rat fetus is well adapted to intrauterine CuDf, it mag; al so be susceptible to hepatic lipid infiltration when the dam is CuDf. (C) 1996 W. B. Saunders Company Ltd