Group IVA phospholipase A(2) activity may mediate prostaglandin F(2alpha)-induced luteal regression in pseudopregnant rats.
We investigated role(s) of luteal group IVA phospholipase A(2) (GIVA PLA(2)) in prostaglandin (PG) F(2alpha)-induced regression in pseudopregnant rats. Prostaglandin F(2alpha) (PGF(2alpha)) treatment of day 6 pseudopregnant rats stimulated luteal PLA(2) activity, which was sensitive to inhibitors and associated with increased GIVA PLA(2) immunoreactivity. Intra-bursal treatment with the enzyme inhibitor (AACOCF3) prior to PGF(2alpha) failed to prevent the initial decline in progesterone but induced subsequently a persistent rise that was significantly higher than that of vehicle-treated group. TUNEL-positive signals in luteal cells of control group were reduced by AACOCF3 treatment. TUNEL-positive reaction induced in luteal cells in vitro by combined cytokines and agonistic anti-Fas were both reduced by AACOCF3 and another inhibitor pyrrophenone. Overall data show that luteal GIVA PLA(2) activity and expression increased following PGF(2alpha) administration and that acute chemical inhibition of this activity could reverse, at least partly, PGF(2alpha)-induced functional regression and prevent apoptosis induced by PGF(2alpha)in vivo and by cytokines in vitro.
Kurusu
Shiro
S
Laboratory of Veterinary Physiology, Kitasato University School of Veterinary Medicine, Towada, Aomori 034-8628, Japan. kurusu@vmas.kitasato-u.ac.jp
Tokunaga
Noriaki
N
Yonezawa
Tomohiro
T
Kawaminami
Mitsumori
M
D000818:Animals; D017209:Apoptosis / Q000502:physiology; D001095:Arachidonic Acids / Q000494:pharmacology; D015237:Dinoprost / Q000378:metabolism*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005260:Female; D007150:Immunohistochemistry; D020287:In Situ Nick-End Labeling; D003341:Luteolysis / Q000502:physiology*; D008297:Male; D054467:Phospholipases A2 / Q000378:metabolism*; D011374:Progesterone / Q000097:blood; D011555:Pseudopregnancy / Q000201:enzymology / Q000378:metabolism* / Q000473:pathology / Q000503:physiopathology*; D011759:Pyrrolidines / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar
D001095:Arachidonic Acids; D004791:Enzyme Inhibitors; D011759:Pyrrolidines; C455981:pyrrophenone; C081565:arachidonyltrifluoromethane; D011374:Progesterone; D015237:Dinoprost; D054467:Phospholipases A2