Intestine, Bone, and Mammary Gland Contributions to Maternal Plasma Calcium Increase after Abrupt Weaning

AbstractThe response of maternal plasma calcium concentration to the abrupt and permanent removal of the suckling pups on Day 13 of lactation was investigated. Maternal plasma calcium did not change at 6 hr or 12 hr following pup removal. At 18 hr and 24 hr after weaning, the maternal plasma calcium concentration increased in mothers consuming either 0.47% calcium or 0.02% calcium diets. At 24 hr after weaning, the plasma calcium increase in mothers consuming low dietary calcium was 55% that of mothers consuming adequate dietary calcium. The contribution of the mammary gland to the plasma calcium increase in rats consuming the low dietary calcium was investigated by removing the mammary glands. Following mammary gland removal, plasma calcium increased 50% compared with mothers that had intact mammary glands. The data suggest that intestinal absorption of calcium and bone calcium mobilization remain stimulated by the lactation process for at least 24 hr after removal of the nursing pups.