Differential regulation of phospholipase A(2) activity and prostaglandin E(2) synthesis in activated and non-activated corpora lutea of lactation by the presence and absence of suckling stimulus in rats.
We investigated content of prostaglandin (PG) E(2), a luteotropic eicosanoid, and phospholipase A(2) (PLA(2)) activity in two distinct states of rat corpora lutea of lactation (LCL). Rats subjected to forced weaning on day 0 postpartum (PP0) had a significant attenuation of progesterone synthesis and LCL weight on PP6 and/or PP3 compared with normally lactating rats. Repeated administration of prolactin (10 IU, twice daily) to weaned rats reversed impaired LCL function and structural development beyond the normal level of lactating animals. From PP3 to PP6, PGE(2) level in lactating LCL was increased while it was not altered in non-lactating LCL. In contrast, PLA(2) activity in the cytosol plus microsome fractions was decreased in lactating LCL and was up-regulated in non-lactating LCL as early as on PP3. This study provides the first evidence for differential regulation of PLA(2) activity and PGE(2) synthesis in activation and activation failure of postpartum CL in rats.
Kurusu
Shiro
S
Laboratory of Veterinary Physiology, Kitasato University School of Veterinary Medicine, Towada, Aomori 034-8628, Japan. kurusu@vmas.kitasato-u.ac.jp
Kamikubo
Manabu
M
Yonezawa
Tomohiro
T
Kawaminami
Mitsumori
M
D000818:Animals; D000833:Animals, Suckling / Q000502:physiology*; D003338:Corpus Luteum / Q000166:cytology / Q000378:metabolism*; D015232:Dinoprostone / Q000096:biosynthesis*; D005260:Female; D007774:Lactation; D008297:Male; D054467:Phospholipases A2 / Q000378:metabolism*; D010902:Pituitary Gland / Q000378:metabolism; D011388:Prolactin / Q000378:metabolism; D051381:Rats
D011388:Prolactin; D054467:Phospholipases A2; D015232:Dinoprostone