포유동물의 생식을 조절하는 다수의 호르몬 가운데 가장 중요한 것들로 난소로부터의 estrogen과 progesterone을 들 수 있다. 반면 다양한 스트레스 인자들은 암컷의 성 반응 행동과 번식을 억제함이 잘 알려졌다. 이러한 스트레스가 가해지는 동안 부신에서는 카테콜아민(catecholamine)이 다량 분비되어 위기 상황에 대처하며 이 과정에서 생식 현상의 억제가 일어나는 것으로 추정된다. 본 연구에서는 생식호르몬 분비와 성 행동 양식에 광범위한

Numerous hormones are involved in the regulation of reproduction. Among them, estrogen and progesterone are the most important ovarian steroid hormones regulating female fertility. On the other hand, diverse stressors impede female receptivity and fertility. Since norepinephrine(NE) and epinephrine(E) are released from the adrenal during stress, it might play a role in stress-induced disruptions of fEmale reproductive parameters. The present study was performed to analyze the changes in adrenal catecholaminergic activities in cycling rats. The tissue content and secretion level of catecholamines were determined by high performance liquid chromatography coupled with electrochemical detector(HPLC-ECD). Adrenomedullary content of norepinephrine(NE) was increased on proestrus stage (59.47 6.86 ug/gland), peaked on diestrus I stage(65.22 5.99 ug/gland), and was nadir on diestrus II stage(41.63 1.33 ug/gland). The highest E content was observed on proestrus stage(361.86 15.58 ug/gland) while the lowest level was on diestrus II stage(285.58 12.25 ug/gland). In addition to these observations, a significant reduction of the NE : E ratio was observed (1 : 4.81 on diestrus I vs 1 : 6.13～7.02 on other stages). In vitro secretion of adrenal NE and E was increased on proestrus stage, peaked on estrus stage, and decreased on diestrus II stage. Interestingly, the NE : E ratio in conditioned media was significantly increased on estrus stage (1 : 3.32 vs 1 : 2.34～2.65 on other stages. The biosynthesis of NE and E is mediated by tyrosine hydroxylase(TH) and phenylethanolamine-N-methyltransferase(PNMT) which acts conversion of tyrosine into DOPA and NE into E, respectively. These finding demonstrated that sex steroids, during setrous cycle, seem to be able to modify the adrenal catecholamines biosynthesis and secretion with stage-specific manner by modulation of the enzyme activities.

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