Effects of pulsatile pituitary adenylate cyclase activating polypeptide (PACAP) on gonadotropin secretion and subunit mRNA levels in perifused rat pituitary cells.
Effects of pulsatile pituitary adenylate cyclase activating polypeptide (PACAP) on gonadotropin secretion and subunit mRNA levels in perifused rat pituitary cells.
复制标题
脉动垂体腺苷酸环化酶激活多肽 (PACAP) 对灌注大鼠垂体细胞中促性腺激素分泌和亚基 mRNA 水平的影响。
DOI：
10.1016/0024-3205(95)00047-a
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发表时间：
1995
期刊：
影响因子：
6.1
通讯作者：
Winters,SJ
中科院分区：
文献类型：
--
作者：
Tsujii,T;Winters,SJ
本文研究了间歇性给予垂体腺苷环化酶激活多肽(PACAP)对7周龄正常大鼠和去大鼠垂体前叶细胞促性腺激素分泌和亚单位mRNA水平的影响。细胞在2.5 nM GnRH或10 nM PACAP的每小时脉冲或单独的培养液中灌流9h。脉冲式促性腺激素释放激素启动促黄体生成素、卵泡刺激素和α亚单位的分泌，但其作用远不如促性腺激素释放激素。尽管脉冲间分泌在整个实验过程中逐渐增加，但反应性随着PACAP的重复脉冲而下降。PACAP对去势大鼠垂体细胞释放黄体生成素的刺激作用略强于正常大鼠。灌流结束后，提取去势大鼠脑垂体RNA，测定促性腺激素亚单位mRNA水平。脉冲式PACAP刺激α亚单位和促黄体生成素β基因表达，但不影响β基因表达。相反，持续的PACAP增加了α亚单位的基因表达水平，但抑制了β基因的表达，而不影响β基因的表达。我们的结论是，脉冲式PACAP单独给药时是一个相对无效的促性腺激素分泌刺激因子，并且与连续的PACAP对促性腺激素亚单位基因表达的调节有很大的不同。我们认为PACAP在体内的分泌方式可能是促性腺激素亚单位基因差异表达的决定因素。
The effects of pituitary adenylate cyclase activating polypeptide (PACAP) administered intermittently on gonadotropin secretion and subunit mRNA levels in anterior pituitary cells from 7wk old intact and orchidectomized rats were studied. Cells were perifused for 9 h with hourly pulses of 2.5 nM GnRH or 10 nM PACAP, or with medium alone. Pulsatile PACAP initiated episodes of LH, FSH and α-subunit secretion, but was much less effective than GnRH. Responsiveness declined with repeated pulses of PACAP, although interpulse secretion increased gradually throughout the experiment. PACAP was a slightly more effective stimulator of LH release by pituitary cells from castrated than intact rats. At the completion of perifusion, pituitary RNA from castrated rats was extracted for measurement of gonadotropin subunit mRNA levels. Pulsatile PACAP stimulated α-subunit and LHβ mRNA levels but did not affect FSHβ mRNA. By contrast, continuous PACAP increased α-subunit mRNA levels, but suppressed FSHβ mRNA without affecting LHβ mRNA. We conclude that pulsatile PACAP is a relatively ineffective stimulator of gonadotropin secretion when administered alone, and regulates gonadotopin subunit gene expression quite differently than continuous PACAP. We propose that the mode of PACAP secretion in vivo may be a determinant of the differential expression of the gonadotropin subunit genes.