title: Bovine luteal prolactin receptor expression: potential involvement in regulation of progesterone during the estrous cycle and pregnancy.
abstract: In the present study, we performed quantitative reverse-transcription PCR (qPCR) to examine changes in gene expression of prolactin receptor (long form: l-PRLR; short form: s-PRLR) and 20α-hydroxysteroid dehydrogenase (20α-HSD; EC 1.1.1.149) in the bovine corpus luteum (CL) throughout the estrous cycle and pregnancy. Western blotting was used to determine protein abundance. Bovine CL were collected and luteal stages (n = 6/stage) were classified by macroscopic observation as early (d 1 to 4 after ovulation), mid (d 5 to 10), late (d 11 to 17), and regressing (d 18 to 20). A CL of pregnancy (n = 6) was determined by the presence of conceptus (d 28 to term). The mRNA for both forms of PRLR were expressed at all the luteal stages. Expression of s-PRLR and l-PRLR mRNA was less (P < 0.01) during early and regressing luteal stages compared with mid and late stages. Expression of s-PRLR mRNA in CL of pregnancy was greater (P < 0.01) than early, mid, and regressing CL and did not differ from late luteal stage expression. A greater (P < 0.01) expression of l-PRLR mRNA was observed in pregnant vs. early and regressing CL. In addition, qPCR showed the presence of 20α-HSD mRNA during all luteal stages of the estrous cycle, with the greatest (P < 0.01) expression observed in the regressing luteal stage. Western blotting revealed protein abundance of both PRLR isoforms during all luteal stages and pregnancy, with a predominance of the s-PRLR protein. Densitometry analysis indicated that protein abundances of s-PRLR were greater (P < 0.05) than l-PRLR during early, mid, and late luteal stages and did not differ during the regressing luteal stage. Protein abundances of 20α-HSD were least (P < 0.05) during the early luteal stage. In conclusion, results of the current study suggest a possible involvement of PRLR, especially s-PRLR, in the regulation of progesterone secretion and metabolism during the bovine estrous cycle and pregnancy.
authors.affiliation: Department of Animal Sciences, University of Florida, Gainesville, FL 32611, USA.
authors.forename: I M
authors.initials: IM
authors.lastname: Thompson
authors.forename: M
authors.initials: M
authors.lastname: Ozawa
authors.forename: J W
authors.initials: JW
authors.lastname: Bubolz
authors.forename: Q
authors.initials: Q
authors.lastname: Yang
authors.forename: G E
authors.initials: GE
authors.lastname: Dahl
mesh_terms: D043607:20-alpha-Hydroxysteroid Dehydrogenase / Q000096:biosynthesis / Q000235:genetics; D000818:Animals; D015153:Blotting, Western / Q000662:veterinary; D002417:Cattle / Q000502:physiology*; D003338:Corpus Luteum / Q000201:enzymology / Q000378:metabolism*; D030762:Estrous Cycle / Q000502:physiology*; D005260:Female; D015971:Gene Expression Regulation, Enzymologic; D011247:Pregnancy; D011374:Progesterone / Q000378:metabolism*; D020033:Protein Isoforms; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D011981:Receptors, Prolactin / Q000096:biosynthesis* / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000662:veterinary
chemical_list: D020033:Protein Isoforms; D012333:RNA, Messenger; D011981:Receptors, Prolactin; D011374:Progesterone; D043607:20-alpha-Hydroxysteroid Dehydrogenase