Chedrese P J, Braileanu G T
Reproductive Biology Research Unit, Department of Obstetrics and Gynecology, Royal University Hospital, 103 Hospital Dr., S7N-OW8, Saskatoon, Sk., Canada.
Endocrine. 1996 Feb;4(1):11-8. doi: 10.1007/BF02738869.
The objective of this study was to investigate the effect of the tumor-promoting phorbol ester phorbol 12-myristate 13-acetate (PMA) on FSH- and LH-induced 3β-HSD-gene expression in cultured porcine granulosa cells. FSH and LH induced a dose dependent increase in the accumulation of 3β-HSD mRNA, measured by Northern blot. A 1.6- to 1.8-fold increase (p<0.01) was observed with 10 ng/mL of FSH or LH. Maximal levels of 2.5- to 2.9-fold increases, relative to control, were reached at 30 and 100 ng/mL of the gonadotropins. When granulosa cells were treated with PMA (100 nM) just before the addition of FSH, the 3β-HSD rnRNA levels induced by 10 or 30 ng/mL of FSH were inhibited or partially inhibited, respectively. PMA did not inhibit elevated levels of 3β-HSD mRNA induced by FSH at concentrations of 100, 300, and 1000 ng/mL. Alternatively, PMA added just before LH, inhibited LH-stimulated 3β-HSD mRNA levels at all doses of LH tested (10, 30, 100, 300, and 1000 ng/mL). The protein kinase A-stimulators, dibutyryl-cAMP (cAMP) (0.5 mM) and forskolin (10 nM), also elevated the 3β-HSD-gene transcription, 3.5- and 4.0-fold respectively. PMA prevented the stimulation of the 3β-HSD-gene transcription when it was added just before cAMP or forskolin. We concluded that stimulation of PKC by PMA appears to have inhibited the gonadotropin-induced increase in 3β-HSD mRNA levels by preventing cAMP-activated 3β-HSD-gene transcription. The data also suggest that the effect of PMA appears to be more specific for regulation of LH-stimulated intracellular signals than those of FSH. This effect may indicate a site of differential regulation of FSH and LH on the stimulation of 3β-HSD-gene transcription.
本研究的目的是调查促肿瘤佛波酯佛波醇12 -肉豆蔻酸酯13 -乙酸酯（PMA）对培养的猪颗粒细胞中促卵泡激素（FSH）和促黄体生成素（LH）诱导的3β -羟类固醇脱氢酶（3β -HSD）基因表达的影响。通过Northern印迹法检测，FSH和LH诱导3β -HSD mRNA积累呈剂量依赖性增加。10 ng/mL的FSH或LH可使3β -HSD mRNA增加1.6至1.8倍（p<0.01）。促性腺激素浓度为30和100 ng/mL时，相对于对照，最大增加水平达到2.5至2.9倍。当在添加FSH之前用PMA（100 nM）处理颗粒细胞时，10或30 ng/mL FSH诱导的3β -HSD mRNA水平分别受到抑制或部分抑制。PMA在100、300和1000 ng/mL浓度下不抑制FSH诱导的3β -HSD mRNA升高水平。另外，在添加LH之前加入PMA，在所有测试的LH剂量（10、30、100、300和1000 ng/mL）下均抑制LH刺激的3β -HSD mRNA水平。蛋白激酶A刺激剂二丁酰环磷腺苷（cAMP）（0.5 mM）和福斯可林（10 nM）也分别使3β -HSD基因转录升高3.5倍和4.0倍。当在cAMP或福斯可林之前加入PMA时，可阻止3β -HSD基因转录的刺激。我们得出结论，PMA对蛋白激酶C的刺激似乎通过阻止cAMP激活的3β -HSD基因转录，抑制了促性腺激素诱导的3β -HSD mRNA水平增加。数据还表明，PMA的作用似乎对LH刺激的细胞内信号调节比对FSH更具特异性。这种作用可能表明FSH和LH在刺激3β -HSD基因转录方面存在差异调节位点。
