Increase in prolactin receptor (PRL-R) mRNA level in the mammary gland after hormonal induction of lactation in virgin ewes.
In order to examine the hormonal regulation of the prolactin-receptor (PRL-R) gene expression during mammary gland development, ewes were treated to induce lactation via an estrogen-progesterone-hydrocortisone and ovine growth hormone treatment. In situ hybridization analysis was used and revealed that sex steroids increased PRL-R mRNA levels in the mammary gland. Using RNase protection assay we showed that the estradiol + progesterone treatment increased both the levels of the long and the short forms of PRL-R mRNA. Addition of hydrocortisone increased the level of alphaS1-casein transcripts and the level of the ratio of the long to the short form of the PRL-R mRNA. This ratio can be further enhanced by addition of ovine growth hormone to the latter treatment. This suggests a role of hydrocortisone and ovine growth hormone in the alternative splicing that leads to the preferential expression of the long form of the PRL-R mRNA. In conclusion, the present experiments suggest that estrogen, progesterone and hydrocortisone are the major regulators of the PRL-R gene expression during pregnancy and prepare the mammary gland for its differentiation.
Cassy
S
S
Laboratoire de Biologie Cellulaire et Moleculaire, Institut National de la Recherche Agronomique, Jouy-en-Josas, France.
Charlier
M
M
Bélair
L
L
Guillomot
M
M
Laud
K
K
Djiane
J
J
D017398:Alternative Splicing / Q000502:physiology; D000818:Animals; D015152:Blotting, Northern / Q000662:veterinary; D017931:DNA Primers / Q000737:chemistry; D004587:Electrophoresis, Agar Gel; D004591:Electrophoresis, Polyacrylamide Gel / Q000662:veterinary; D004967:Estrogens / Q000502:physiology; D005260:Female; D018507:Gene Expression Regulation, Developmental; D013006:Growth Hormone / Q000502:physiology; D006854:Hydrocortisone / Q000502:physiology; D007091:Image Processing, Computer-Assisted; D017403:In Situ Hybridization / Q000662:veterinary; D007774:Lactation; D008321:Mammary Glands, Animal / Q000254:growth & development / Q000502:physiology*; D011374:Progesterone / Q000502:physiology; D012333:RNA, Messenger / Q000096:biosynthesis / Q000737:chemistry / Q000302:isolation & purification; D011981:Receptors, Prolactin / Q000032:analysis / Q000235:genetics* / Q000502:physiology; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000662:veterinary; D012260:Ribonucleases / Q000737:chemistry; D012756:Sheep / Q000254:growth & development / Q000502:physiology*
D017931:DNA Primers; D004967:Estrogens; D012333:RNA, Messenger; D011981:Receptors, Prolactin; D011374:Progesterone; D013006:Growth Hormone; D012260:Ribonucleases; D006854:Hydrocortisone