Glucocorticoid counteracts the suppressive effect of tumor necrosis factor-alpha on the surge of luteinizing hormone secretion in rats.
We have previously reported that tumor necrosis factor-alpha (TNF-alpha) suppressed pulsatile secretion of luteinizing hormone (LH) in adrenalectomized (ADX) rats, which was restored by replacement of glucocorticoid. In the present study, we examined the role of glucocorticoid in inducing the preovulatory LH surge under conditions of infectious stress. Intravenous injection of TNF-alpha (1 microg) into the proestrous rats at 1300 h attenuated the LH surge and decreased the number of oocytes ovulated. The inhibitory effect of TNF-alpha on the LH surge was blocked by pretreatment with indomethacin, suggesting that the effects of TNF-alpha were mediated by prostaglandins (PGs). On the other hand, ADX markedly enhanced the inhibitory effect of TNF-alpha on the LH surge and subsequent ovulation, which was almost completely restored by pretreatment with a subcutaneous injection of corticosterone (10 mg). These results suggest that glucocorticoid counteracts the inhibitory effect of the cytokines on the preovulatory LH surge by suppressing PG synthesis, and thereby helps to maintain reproductive function under infectious stress conditions.
Matsuwaki
Takashi
T
Department of Veterinary Physiology, Veterinary Medical Science, The University of Tokyo, Tokyo 113-8657, Japan. amnishi@mail.ecc.u-tokyo.ac.jp
Suzuki
Masatoshi
M
Yamanouchi
Keitaro
K
Nishihara
Masugi
M
D000315:Adrenalectomy; D000818:Animals; D003345:Corticosterone / Q000097:blood / Q000494:pharmacology*; D016861:Cyclooxygenase Inhibitors / Q000494:pharmacology*; D005260:Female; D007213:Indomethacin / Q000494:pharmacology*; D007986:Luteinizing Hormone / Q000097:blood / Q000378:metabolism*; D010060:Ovulation / Q000187:drug effects; D011359:Proestrus / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D012636:Secretory Rate / Q000187:drug effects; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology*
D016861:Cyclooxygenase Inhibitors; D014409:Tumor Necrosis Factor-alpha; D007986:Luteinizing Hormone; D003345:Corticosterone; D007213:Indomethacin