Molecular species of prostaglandins involved in modulating luteinising hormone pulses of female rats under infectious stress conditions.
Mammalian reproductive function is controlled by the hypothalamic-pituitary-gonadal (HPG) axis, which is suppressed under infectious stress conditions. By analysing the pulsatility of luteinising hormone (LH), we have previously demonstrated that prostaglandins (PGs) in the central nervous system mediate infectious stress to suppress the activity of the HPG axis. The present study aimed to characterise the types of PGs responsible for suppression of the HPG axis. We focused on three major types of PGs: PGE2 , PGD2 and PGF2α . We used female rats overiectomised bilaterally 1 week before the experiments. Lipopolysaccharide (100 μg kg-1 ) suppressed LH pulses at the same time as enhancing the concentration of all three PGs in the cerebrospinal fluid, which was restored by indomethacin (10 mg kg-1 ). Subsequently, we observed LH pulsatility after a single injection of each PG and after co-injection of PGE2 with PGF2α into the third cerebral ventricle. A single injection of PGE2 dose-dependently induced a transient increase in mean LH concentration and LH pulse amplitude, and PGD2 significantly increased the amplitude of LH pulses, wereas PGF2α did not affect LH pulsatility. On the other hand, co-injection of PGE2 and PGF2α induced a significant suppression of both the frequency and amplitude of LH pulses. These results suggest that PGE2 and PGF2α can represent two of the mediators that suppress the HPG axis in situations of infectious stress. Moreover, the results imply that there are two contradictory effects of PGE2 on LH pulsatility: (i) enhancive when working alone and (ii) suppressive when working together with PGF2α .
['Matsuwaki|T|T|0000-0002-4842-6110', 'Komatsuda|M|M|', 'Fujisawa|A|A|', 'Doke|M|M|', 'Yamanouchi|K|K|', 'Nishihara|M|M|']
D000818:Animals D016861:Cyclooxygenase Inhibitors D015237:Dinoprost D015232:Dinoprostone D005260:Female D007030:Hypothalamo-Hypophyseal System D007213:Indomethacin D008070:Lipopolysaccharides D007986:Luteinizing Hormone D010052:Ovariectomy D015230:Prostaglandin D2 D051381:Rats D017208:Rats, Wistar D013312:Stress, Physiological
infectious stress LH pulse PGE
2 PGF
2α hypothalamus