Evidence suggesting multiple promoting roles of luteal group IVA phospholipase A(2) in prostaglandin F(2alpha)-induced regression in pseudopregnant rats.
We evaluated effects of local administration of selective inhibitors of group IVA phospholipase A(2) (GIVA PLA(2)) and cyclooxygenase (COX) on exogenous prostaglandin (PG) F(2alpha)-induced luteal regression in pseudopregnant rats. Intra-bursal treatment with a GIVA PLA(2) inhibitor AACOCF(3) just prior to PGF(2alpha) (30microg, subcutaneously) on day 6 of pseudopregnancy (PSP6) prevented a decline in circulating progesterone and inhibited TUNEL-positive reactions of steroidogenic cell. Its treatment on PSP9 failed to inhibit functional regression, but reduced significantly apoptosis of steroidogenic cells and vascular endothelial cells, and suppressed the infiltration of macrophages. A COX-2-selective inhibitor NS398 inhibited the decline of progesterone and apoptosis of steroidogenic cells on PSP6 but not on PSP9. A COX-1 inhibitor SC560 exerted insignificant anti-luteolytic effects. Overall data suggest that luteal GIVA PLA(2) plays multiple promoting roles in PGF(2alpha)-induced luteal regression at least partly by a COX-2 activity-related mechanism in pseudopregnant rats.
Kurusu
Shiro
S
Laboratory of Veterinary Physiology, Kitasato University School of Veterinary Medicine, Higashi 23-35-1, Towada, Aomori 034-8628, Japan. kurusu@vmas.kitasato-u.ac.jp
Sonoda
Norifumi
N
Nakahara
Masato
M
Yonezawa
Tomohiro
T
Kawaminami
Mitsumori
M
D000818:Animals; D017209:Apoptosis; D051546:Cyclooxygenase 2 / Q000378:metabolism; D015237:Dinoprost / Q000494:pharmacology*; D005260:Female; D054513:Group IV Phospholipases A2 / Q000378:metabolism*; D003341:Luteolysis / Q000378:metabolism*; D011555:Pseudopregnancy / Q000201:enzymology; D051381:Rats
D015237:Dinoprost; D051546:Cyclooxygenase 2; D054513:Group IV Phospholipases A2