The expression of forms of prolactin receptors in splenocytes and thymocytes of neonatal rats: the effect of milk ingestion.
Because prolactin (PRL) plays a role in neonatal immune development, we examined the expression of prolactin receptors (PRL-R) in neonatal lymphoid tissues. We had shown previously that deprivation of milk-borne PRL, days 2-5 in the neonatal rat, leads to enhanced in vitro mitogenesis of thymocytes and splenocytes as well as a change in lymphoid-specific, cell surface antigens (GROVE et al. 1991). In this present study, we asked if neonatal lymphocytes express PRL-R; which forms of PRL-R are expressed (long vs. short form); when these forms are expressed during development; and if milk ingestion plays a role in receptor expression. Two approaches were taken using neonatal rat thymocytes and splenocytes: RNA was analyzed by polymerase chain reaction (PCR) and cells were stained with antibody to PRL-R and analyzed by flow cytometry. In regard to cell surface expression, the percentage of PRL-R positive splenocytes was greater than thymocytes at all ages tested. In the spleen, the percentage of PRL-R positive cells gradually increased to adult levels by day 10; in the thymus the percentage fell to adult levels by the first day after birth. Finally, milk ingestion in the first 7 h decreased the percentage of cells expressing cell surface PRL-R. Tissues from animals deprived of milk during this time expressed PRL-R at the same level as the newborn.
Günes
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Department of Molecular and Cell Biology, Pennsylvania State University, University Park 16802.
Grove
D S
DS
Bour
B
B
Zawilla
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S
Mastro
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AM
D000284:Administration, Oral; D000818:Animals; D000831:Animals, Newborn / Q000502:physiology*; D001483:Base Sequence; D015139:Blotting, Southern; D002478:Cells, Cultured; D005260:Female; D005434:Flow Cytometry; D066298:In Vitro Techniques; D008297:Male; D008892:Milk / Q000378:metabolism* / Q000502:physiology; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction; D011247:Pregnancy; D012333:RNA, Messenger / Q000032:analysis / Q000235:genetics; D051381:Rats; D017207:Rats, Sprague-Dawley; D011981:Receptors, Prolactin / Q000032:analysis / Q000235:genetics / Q000502:physiology*; D013154:Spleen / Q000737:chemistry / Q000166:cytology* / Q000502:physiology; D013950:Thymus Gland / Q000737:chemistry / Q000166:cytology* / Q000502:physiology
D012333:RNA, Messenger; D011981:Receptors, Prolactin