Kurowicka Beata, Gajewska Alina, Franczak Anita
Department of Animal Physiology, University of Warmia and Mazury in Olsztyn, Oczapowski Str. 1A, 10-719 Olsztyn, Poland.
Reprod Biol. 2006 Mar;6(1):63-77.
The reproductive system fully develops during postnatal stages of life, and as such it may be susceptible to environmental cues such as high temperature. Thus, the purpose of the study was to compare how exposure to 34 degrees Celsius ambient temperature affects pituitary-gonadal axis of immature and adult female rats. Three groups of females at proestrous or metaestrous (n=38) were used in the study. The females were housed in ambient temperature of 34 degrees Celsius (WR group, n=10) or room temperature (CR group, n=16) from birth to adulthood. The females from the third group were acclimated to 34 degrees Celsius as adults (WA group, n=12). In the WR group the onset of puberty was delayed in comparison to the CR group. The plasma PRL level was lower during proestrous and higher during metaestrous in the WR group compared to the CR group. During metaestrous, lower FSH and higher progesterone (P(4)) plasma concentrations were found in the WR females. No changes in LH and oestradiol (E(2)) plasma concentrations were demonstrated. Higher in vitro E(2) and lower P(4) secretions under FSH stimulation were observed in the WR follicles compared to those of the CR group. The WR group also demonstrated higher basal and LH-stimulated luteal in vitro secretion of P(4) than controls. Plasma LH and FSH concentrations during metaestrous were higher in WA females than in the WR group, but PRL level was lower. Follicles of the WA group were unresponsive to FSH with respect to steroid secretion. In addition, LH stimulated luteal E(2) secretion in this group. P(4) release by luteal cells was lower in the WA than in the WR group. We concluded that WR females differ from WA in reproductive system adjustments to rearing temperature and that early thermal experience is more effective in antagonizing the effect of high temperature than acclimation of adult females.
生殖系统在出生后的生命阶段完全发育，因此它可能易受高温等环境因素的影响。因此，本研究的目的是比较暴露于34摄氏度环境温度对未成熟和成年雌性大鼠垂体-性腺轴的影响。研究中使用了三组处于动情前期或动情后期的雌性大鼠（n = 38）。这些雌性大鼠从出生到成年都饲养在34摄氏度的环境温度下（WR组，n = 10）或室温下（CR组，n = 16）。第三组雌性大鼠成年后适应34摄氏度（WA组，n = 12）。与CR组相比，WR组的青春期开始延迟。与CR组相比，WR组在动情前期血浆PRL水平较低，在动情后期较高。在动情后期，WR组雌性大鼠的FSH血浆浓度较低，孕酮（P(4)）血浆浓度较高。未发现LH和雌二醇（E(2)）血浆浓度有变化。与CR组相比，WR组卵泡在FSH刺激下的体外E(2)分泌较高，P(4)分泌较低。WR组还显示出比对照组更高的基础和LH刺激的黄体体外P(4)分泌。WA组雌性大鼠在动情后期的血浆LH和FSH浓度高于WR组，但PRL水平较低。WA组的卵泡在类固醇分泌方面对FSH无反应。此外，LH刺激了该组黄体的E(2)分泌。WA组黄体细胞的P(4)释放低于WR组。我们得出结论，WR组雌性大鼠在生殖系统对饲养温度的调整方面与WA组不同，并且早期热暴露在对抗高温影响方面比成年雌性大鼠的适应更有效。
