title: Polymeric-Ig receptor gene expression in rabbit mammary gland during pregnancy and lactation: evolution and hormonal regulation.
abstract: The polymeric immunoglobulin receptor (poly Ig-R) mediates transcytosis of IgA and IgM antibodies produced by local plasma cells across epithelial cells of mucosal and glandular tissues. Gene expression of the poly-Ig R was analyzed in rabbit mammary gland during pregnancy and lactation. The poly Ig-R was expressed as early as day 8 (G8) of gestation and mRNA accumulation remained low until about G18. From G21, the mRNA abundance increased and reached steady state levels approximately 5-fold higher at day 15 of lactation (L15) when compared to basal levels at G8. The hormonal regulation of poly-Ig receptor gene expression was assessed in mammary organ cultures. Poly-Ig R mRNA accumulation in mammary explants cultured for 24 or 48 h in the presence of ovine prolactin (oPRL) was significantly increased to a maximal 4-fold level at 1 microgram ml-1 of oPRL. Estradiol (100 pg ml-1) or progesterone (1 microgram ml-1) did not further stimulate poly-Ig R expression. In contrast, their combination resulted in a significant 30-50% decrease of poly-Ig-R mRNA levels. The addition of 1 microgram ml-1 of cortisol to medium in the absence or presence of estradiol or progesterone decreased the amount of poly-Ig-R mRNA. The results suggest that until mid-pregnancy, poly-Ig-R expression is inhibited by elevated progesterone-estradiol concentrations and that the subsequent increase is due to the concomitant decrease of the two circulating steroids and the increase of serum prolactin levels.
authors.affiliation: Unité d'Endocrinologie Moléculaire, INRA, Centre de Recherches de Jouy en Josas, France.
authors.forename: R
authors.initials: R
authors.lastname: Rosato
authors.forename: H
authors.initials: H
authors.lastname: Jammes
authors.forename: L
authors.initials: L
authors.lastname: Belair
authors.forename: C
authors.initials: C
authors.lastname: Puissant
authors.forename: J P
authors.initials: JP
authors.lastname: Kraehenbuhl
authors.forename: J
authors.initials: J
authors.lastname: Djiane
mesh_terms: D000818:Animals; D004958:Estradiol / Q000494:pharmacology; D005260:Female; D015870:Gene Expression / Q000187:drug effects; D006854:Hydrocortisone / Q000494:pharmacology; D007774:Lactation / Q000502:physiology*; D008321:Mammary Glands, Animal / Q000378:metabolism*; D011247:Pregnancy; D011270:Pregnancy, Animal / Q000378:metabolism*; D011374:Progesterone / Q000494:pharmacology; D011388:Prolactin / Q000494:pharmacology; D012333:RNA, Messenger / Q000378:metabolism; D011817:Rabbits; D012635:Secretory Component / Q000235:genetics*
chemical_list: D012333:RNA, Messenger; D012635:Secretory Component; D011374:Progesterone; D004958:Estradiol; D011388:Prolactin; D006854:Hydrocortisone