Parathyroid hormone-related protein in preterm human milk.
BACKGROUND
Parathyroid hormone-related protein (PTHrP) has the ability to activate parathyroid hormone receptors and cause hypercalcemia. High concentrations of PTHrP are found in human breastmilk of mothers of term-infants. It is not known whether PTHrP is excreted in preterm human milk. This study tested the hypothesis that PTHrP concentrations in milk obtained from mothers of preterm infants are similar to those found in milk from mothers of term infants.


METHODS
We collected samples of expressed human milk obtained from 27 mothers of preterm infants (27-34 weeks' gestation) and from 16 mothers of full-term infants. Samples were collected within the first 72 hours postpartum (colostrum) and again at 1 and 2 weeks postpartum. PTHrP concentrations in these samples were measured by two-site immunoradiometric assay.


RESULTS
PTHrP concentrations were significantly higher in samples obtained after 1 week postpartum than in samples obtained during the first 72 hours of life in breastmilk obtained from mothers of both term and preterm infants (P < 0.0001). PTHrP concentrations were similar in colostrum and after 1 week in term and preterm milk. PTHrP concentrations after 2 weeks of lactation were significantly higher in samples obtained from mothers of term infants (P < 0.006).


CONCLUSIONS
Human milk expressed by mothers of preterm infants contains amounts of PTHrP similar to those measured in milk expressed by mothers of term infants.
Lubetzky
Ronit
R
Department of Neonatology, Tel Aviv Sourasky Medical Center, Tel Aviv, Israel.
Weisman
Yosef
Y
Dollberg
Shaul
S
Herman
Lea
L
Mandel
Dror
D
D000328:Adult; D016022:Case-Control Studies; D003126:Colostrum / Q000737:chemistry; D005260:Female; D005865:Gestational Age; D006801:Humans; D007231:Infant, Newborn; D007234:Infant, Premature; D007774:Lactation / Q000378:metabolism*; D008297:Male; D008895:Milk, Human / Q000737:chemistry*; D044162:Parathyroid Hormone-Related Protein / Q000032:analysis*; D049590:Postpartum Period; D011247:Pregnancy; D013997:Time Factors
D044162:Parathyroid Hormone-Related Protein