Acquisition of luteolytic capacity involves differential regulation by prostaglandin F2alpha of genes involved in progesterone biosynthesis in the porcine corpus luteum.
Luteolytic capacity is defined as the ability of corpora lutea (CL) to undergo luteolysis after prostaglandin (PG) F2alpha treatment. The mechanisms causing acquisition of luteolytic capacity are not yet identified but CL without luteolytic capacity have PGF2alpha receptors and respond to PGF2alpha with some changes in gene expression. Inhibition of progesterone biosynthesis is a key feature of luteolysis and therefore we postulated that genes involved in progesterone biosynthesis would be regulated by PGF2alpha differently in CL with or without luteolytic capacity. Gilts on day 9 after estrus (lack luteolytic capacity) or day 17 of pseudopregnancy (with luteolytic capacity) were treated with saline or a PGF2alpha analog (cloprostenol) and CL were collected 0.5 (Experiment I) or 10 h (Experiment II) later. In Experiment III, large luteal cells from CL on day 9 or 17 were cultured for 1, 12 and 24h with or without PGF2alpha. PGF2alpha decreased LDL receptor mRNA (27%), steroidogenic acute regulatory protein (StAR) mRNA (41%), StAR protein (75%), LH receptor mRNA (55%), and LH receptor protein (45%) at 10 h after treatment in day 17 but not day 9 CL. PGF2alpha increased DAX-1 mRNA at 0.5 h (43%) and 10 h (46%) after PGF2alpha in day 17 but not day 9 CL but decreased 3betaHSD mRNA ( approximately 20% at 10 h) in both days 9 and 17 CL. In vitro, PGF2alpha decreased StAR mRNA at 12 h only in day 17 luteal cells; however, continuous treatment with PGF2alpha for 24 h decreased StAR mRNA in both days 9 and 17 luteal cells. Thus, luteolytic capacity involves a critical change in responsiveness of DAX-1, StAR, and LH receptor to PGF2alpha that results in inhibition of luteal progesterone biosynthesis.
Diaz
Francisco J
FJ
Endocrinology-Reproductive Physiology Program, Department of Dairy Science, University of Wisconsin-Madison, 1675 Observatory Drive, Madison, WI 53706-1284, USA.
Wiltbank
Milo C
MC
D000818:Animals; D015153:Blotting, Western / Q000662:veterinary; D003338:Corpus Luteum / Q000378:metabolism / Q000502:physiology*; D057137:DAX-1 Orphan Nuclear Receptor; D004268:DNA-Binding Proteins / Q000096:biosynthesis / Q000235:genetics; D015237:Dinoprost / Q000494:pharmacology*; D005260:Female; D005786:Gene Expression Regulation / Q000187:drug effects* / Q000502:physiology; D006913:Hydroxysteroid Dehydrogenases / Q000096:biosynthesis / Q000235:genetics; D003341:Luteolysis / Q000235:genetics / Q000378:metabolism; D010750:Phosphoproteins / Q000096:biosynthesis / Q000235:genetics; D011374:Progesterone / Q000096:biosynthesis* / Q000235:genetics; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D011973:Receptors, LDL / Q000096:biosynthesis / Q000235:genetics; D011974:Receptors, LH / Q000096:biosynthesis / Q000235:genetics; D018168:Receptors, Retinoic Acid / Q000096:biosynthesis / Q000235:genetics; D012097:Repressor Proteins / Q000096:biosynthesis / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000662:veterinary; D013552:Swine / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D000098682:Steroidogenic Acute Regulatory Protein
D057137:DAX-1 Orphan Nuclear Receptor; D004268:DNA-Binding Proteins; D010750:Phosphoproteins; D012333:RNA, Messenger; D011973:Receptors, LDL; D011974:Receptors, LH; D018168:Receptors, Retinoic Acid; D012097:Repressor Proteins; D000098682:Steroidogenic Acute Regulatory Protein; D011374:Progesterone; D015237:Dinoprost; D006913:Hydroxysteroid Dehydrogenases