DOWN-REGULATION OF PROGESTIN RECEPTORS IN GUINEA-PIG BRAIN - NEW FINDINGS USING AN IMMUNOCYTOCHEMICAL TECHNIQUE
DOWN-REGULATION OF PROGESTIN RECEPTORS IN GUINEA-PIG BRAIN - NEW FINDINGS USING AN IMMUNOCYTOCHEMICAL TECHNIQUE
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DOI：
10.1002/neu.480210502
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发表时间：
1990-07-01
期刊：
影响因子：
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通讯作者：
TURCOTTE, JC
中科院分区：
文献类型：
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作者：
BLAUSTEIN, JD;TURCOTTE, JC
体外结合实验表明，雌二醇刺激的去势豚鼠注射黄体酮后，下丘脑孕激素受体表达下调。为了确定孕酮是否也减少了孕激素受体的免疫染色，以及孕激素受体在特定的神经解剖区域是否优先下调，去势的豚鼠被注射了剂量的苯甲酸雌二醇(在注射孕酮前42小时为10微克)和孕酮(在灌流前4、12或24小时为500微克)，它们可靠地诱导了前凸的表达和随后对孕酮的行为耐受。从视前区和下丘脑的不同部分切片中计数孕激素受体免疫反应阳性细胞。正如预期的那样，雌二醇显著增加了细胞核，并在较小程度上增加了视前区和下丘脑特定区域的胞浆免疫染色。注射孕酮后12h，孕激素受体免疫反应阳性细胞在某些区域有所减少，但在其他区域无明显变化。下丘脑腹外侧的吻侧和尾侧特别敏感，注射后12小时孕激素受体免疫反应性显著下降。在所检查的任何视前区，孕激素受体免疫反应细胞数量都没有减少，尽管免疫染色强度有明显的下降。这些免疫细胞化学实验的结果扩展了体外孕激素结合实验的早期发现，并表明与孕激素结合一样，当在行为脱敏过程中注射孕酮时，孕激素受体免疫反应性降低。此外，他们指出，下丘脑腹外侧是孕激素受体下调可能对孕酮特别敏感的一个部位。
Progesterone injection in estradiol-primed, ovariectomized guinea pigs results in down-regulation of hypothalamic progestin receptors determined by in vitro binding assays. In order to determine if progesterone also decreases immunostaining of progestin receptors and if progestin receptors are down-regulated preferentially in particular neuroanatomical areas, ovariectomized guinea pigs were injected with doses of estradiol benzoate (10 .mu.g at 42 h before progesterone injection) and progesterone (500 .mu.g at 4, 12, or 24 h before perfusion) that reliably induce the expression of lordosis and subsequent behavioral refractoriness to progesterone. Progestin receptor-immunoreactive cells were counted in sections from discrete parts of the preoptic area and hypothalamus. As expected, estradiol dramatically increased cell nuclear, and, to a lesser extent, cytoplasmic, immunostaining in defined regions of the preoptic area and hypothalamus. By 12 h after progesterone injection, the number of progestin receptor-immunoreactive cells had decreased in some area, but not others. The rostral and caudal aspects of the ventrolateral hypothalamus were particularly responsive showing a substantial decrease in progestin receptor-immunoreactivity by 12 h after injection. No decreases in the progestin receptor-immunoreactive cell number were observed in any of the preoptic regions examined, although obvious decreases in immunostaining intensity were seen. The results of these immunocytochemical experiments extend earlier findings from in vitro progestin binding experiments and demonstrate that as with progestin binding, progestin receptor-immunoreactivity decreases when progesterone is injected in a behavioral desensitization procedure. Furthermore, they point to the ventrolateral hypothalamus as one site in which the down-regulation of progestin receptors may be particularly responsive to progesterone.