title: Changes in prostaglandin secretion by the regressing bovine corpus luteum.
abstract: Secretion of prostaglandins (PGs) by the regressing corpus luteum (CL) was investigated in the cow. Six cows were implanted with microcapillary dialysis membranes of a microdialysis system (MDS) into the CL during Days 8-9 (Day 0 = estrus), and a prostaglandin (PG) F2alpha analogue (Estrumate) was injected intramuscularly (i.m.) to induce luteolysis. Acute increases in intraluteal release of PGF2alpha and PGE2 were observed during the first 4 h, followed by decreases over the next 8 h. Intraluteal release of both PGs gradually increased again during the period 48-72 h. Concentrations of PGF2alpha in ovarian venous plasma (OVP) were 4-13 times higher than those of jugular venous plasma (JVP) (P < 0.001) during the period of the experiment, and increased from 24 h after treatment with Estrumate (P < 0.05). Cyclooxygenase (COX)-2 mRNA expression increased (P < 0.05) at 2 and 24 h after treatment with Estrumate. The results indicated that local release of PGF2alpha and PGE2, and COX-2 mRNA expression were increased by Estrumate in the regressing CL at the later stages of luteolysis. Thus, luteal secretion of PGs may be involved in the local mechanism for structural rather than functional luteolysis.
authors.affiliation: Department of Animal Science, Obihiro University of Agriculture and Veterinary Medicine, Obihiro 080-8555, Japan.
authors.forename: Kanako
authors.initials: K
authors.lastname: Hayashi
authors.forename: Tomas J
authors.initials: TJ
authors.lastname: Acosta
authors.forename: Bajram
authors.initials: B
authors.lastname: Berisha
authors.forename: Shu-ichi
authors.initials: S
authors.lastname: Kobayashi
authors.forename: Masayuki
authors.initials: M
authors.lastname: Ohtani
authors.forename: Dieter
authors.initials: D
authors.lastname: Schams
authors.forename: Akio
authors.initials: A
authors.lastname: Miyamoto
mesh_terms: D000818:Animals; D002417:Cattle; D003008:Cloprostenol / Q000494:pharmacology; D003338:Corpus Luteum / Q000378:metabolism*; D051546:Cyclooxygenase 2; D015237:Dinoprost / Q000378:metabolism; D015232:Dinoprostone / Q000378:metabolism; D005260:Female; D007527:Isoenzymes / Q000378:metabolism; D011451:Prostaglandin-Endoperoxide Synthases / Q000378:metabolism; D011453:Prostaglandins / Q000378:metabolism*; D012313:RNA / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013997:Time Factors
chemical_list: D007527:Isoenzymes; D011453:Prostaglandins; D012333:RNA, Messenger; D003008:Cloprostenol; D012313:RNA; D015237:Dinoprost; D051546:Cyclooxygenase 2; D011451:Prostaglandin-Endoperoxide Synthases; D015232:Dinoprostone