title: Changes in serum parathyroid hormone-related protein in breastfed preterm infants.
abstract: BACKGROUND
  Parathyroid hormone-related protein (PTHrP) has the ability to activate parathyroid hormone receptors and cause hypercalcemia. In a previous study we have demonstrated high concentrations of PTHrP in both term and preterm human milk (HM). PTHrP intestinal absorption and its influence upon calcium homeostasis of the preterm infant have not been studied yet. This study assessed the correlation between PTHrP concentrations in preterm HM and PTHrP in maternal and neonatal serum.
  
  
  METHODS
  We collected samples of expressed HM obtained from 16 mothers of preterm infants (25-34 weeks of gestation) and drew blood samples from both mothers and infants on postpartum days 2 and 10. PTHrP concentrations were measured by two-site immunoradiometric assay. Blood calcium (Ca), phosphorus (P), and alkaline phosphatase (ALP) concentrations were also measured.
  
  
  RESULTS
  Neither maternal nor neonatal PTHrP serum concentrations varied significantly after 10 days of breastfeeding. There was a correlation between PTHrP concentrations in maternal serum and HM concentrations (R² = 0.24, p = 0.04), but not between HM and neonatal serum concentrations or between PTHrP concentrations in HM and preterm serum concentrations of Ca, P, and ALP.
  
  
  CONCLUSIONS
  Despite high concentrations of PTHrP in preterm HM, serum concentrations of PTHrP of breastfed preterm infants did not increase over time. There was no correlation between PTHrP concentrations in HM and neonatal serum Ca concentration.
authors.affiliation: Department of Neonatology, Lis Maternity Hospital, Tel Aviv Sourasky Medical Center, Israel.
authors.forename: Amir Ben
authors.initials: AB
authors.lastname: Tov
authors.forename: Dror
authors.initials: D
authors.lastname: Mandel
authors.forename: Yossef
authors.initials: Y
authors.lastname: Weissman
authors.forename: Shaul
authors.initials: S
authors.lastname: Dollberg
authors.forename: Tali
authors.initials: T
authors.lastname: Taxir
authors.forename: Ronit
authors.initials: R
authors.lastname: Lubetzky
mesh_terms: D000328:Adult; D001942:Breast Feeding; D005260:Female; D006706:Homeostasis; D006801:Humans; D006934:Hypercalcemia / Q000097:blood / Q000453:epidemiology / Q000378:metabolism*; D015592:Immunoradiometric Assay; D007231:Infant, Newborn; D007234:Infant, Premature; D008297:Male; D008875:Middle Aged; D008895:Milk, Human / Q000378:metabolism*; D044162:Parathyroid Hormone-Related Protein / Q000037:antagonists & inhibitors / Q000097:blood / Q000378:metabolism*; D011247:Pregnancy; D018016:Receptors, Parathyroid Hormone / Q000097:blood / Q000378:metabolism*
chemical_list: D044162:Parathyroid Hormone-Related Protein; D018016:Receptors, Parathyroid Hormone