Banks P K, Inkster S E, White N, Jeffcoate S L
J Endocrinol. 1986 Nov;111(2):199-204. doi: 10.1677/joe.0.1110199.
Catecholoestrogens are naturally occurring metabolites of oestrogens which are found in brain tissue and for which a neuroendocrine role has been postulated. However, reports of their effects on prolactin secretion are ambiguous and as yet no defined function has been attributed to them. The effects of 2-hydroxyoestradiol (2-OHE2) and dopamine on the release of prolactin in vitro by perfused pituitary glands from normal adult female rats at different stages of the oestrous cycle have been investigated. The purity and stability of the 2-OHE2 preparation before and after exposure to pituitary tissue was confirmed by radioenzymatic assay and subsequent thin-layer chromatography. Dopamine (500 nmol/l, 100 nmol/l) was found consistently to suppress release by 60%; this effect was immediate and reversible upon removal of the dopamine. In contrast, the effects of 2-OHE2 (10 nmol/l, 100 nmol/l) were found to vary during the cycle. No effect on prolactin release was evident during either dioestrus or pro-oestrus, but during oestrus a similar, though less potent, suppression of prolactin secretion to that of dopamine was observed (35% suppression compared with controls). The cyclical variation in the suppressive effect of 2-OHE2 on prolactin secretion in the female rat is compatible with a postulated neuroendocrine role for this catecholoestrogen.
儿茶酚雌激素是雌激素的天然代谢产物，存在于脑组织中，并且已推测其具有神经内分泌作用。然而，关于它们对催乳素分泌影响的报道并不明确，迄今为止尚未赋予它们明确的功能。研究了2-羟雌二醇（2-OHE2）和多巴胺对处于发情周期不同阶段的正常成年雌性大鼠灌流垂体在体外释放催乳素的影响。通过放射酶测定法和随后的薄层色谱法确认了2-OHE2制剂在暴露于垂体组织前后的纯度和稳定性。发现多巴胺（500 nmol/l，100 nmol/l）始终能抑制释放60%；这种作用是即时的，去除多巴胺后可逆。相比之下，发现2-OHE2（10 nmol/l，100 nmol/l）的作用在整个周期中有所不同。在间情期或发情前期对催乳素释放均无明显影响，但在发情期观察到对催乳素分泌的抑制作用与多巴胺相似，不过效力较弱（与对照组相比抑制35%）。2-OHE2对雌性大鼠催乳素分泌抑制作用的周期性变化与这种儿茶酚雌激素假定的神经内分泌作用相符。
