Copper metabolism in pregnant and pospartum rat and pups.

A detailed study was made of copper metabolism in rats during and after pregnancy and in the fetuses and pups up to the age of 6 wk. Maternal ceruloplasmin levels increase only briefly at the beginning of the third (and last) week of pregnancy. They then decrease to normal levels at term and decrease markedly in the early postpartum period. Bilary excretion of copper and 67Cu almost stops at term and remains decreased for 2 wk. In spite of this, there is no increase in hepatic copper levels. Except for a 1- to 2-day period shortly after delivery, maternal rats have a positive copper balance if lacteal elimination of copper is ignored. Levels of copper in milk drop at about the fourth day postpartum. Fetal hepatic copper levels are already above adult levels, but the concentration almost doubles during the first week after birth; it decreases to adult levels by 6 wk of age. Ceruloplasmin levels, which are found to be very low in the pups at birth, increase sharply in the first 24 h and quickly achieve adult levels. Large quantitative differences also occur between the pups and adults in concentrations of copper in the brain and kidney. Qualitative differences, measured with 67Cu, are most notable when the neonatal liver is compared with the adult liver.