Barnea A, Cho G, Hajibeigi A, Aguila M C, Magni P
Department of Obstetrics and Gynecology, University of Texas Southwestern Medical Center, Dallas 75235.
Endocrinology. 1991 Aug;129(2):931-8. doi: 10.1210/endo-129-2-931.
Neuropeptide-Y (NPY) and glucocorticoid receptors are coexpressed in many neurons in the brain. We addressed the question: Do glucocorticoids regulate the accumulation and/or secretion of immunoreactive (IR) NPY by fetal rat brain cells in culture, and if so, is the effect developmental stage dependent? Aggregates, formed from dissociated cells obtained from the hypothalamus-olfactory tubercle of 17-day-old fetuses, were cultured in serum-free medium for 23 days. On day 23, the aggregate NPY content was 6 ng/flask, and secretion (last 2 days) was approximately 12 ng/24 h. Exposure to dexamethasone (Dex; 20 nM) between days 0-23 led to a 1.9-fold increase in the aggregate content of NPY, whereas NPY secretion was not altered. When Dex exposure was limited to days 12-23, 16-23, 19-23, or 21-23, only a 12- to 23-day exposure induced NPY accumulation, and it was as effective as a 0- to 23-day exposure. The Dex-induced increase in NPY content was evident after a lag period of 4 days or more. When Dex exposure occurred on days 0-12, the aggregate NPY content on day 12 or 23 was not altered. None of these treatments altered the aggregate/medium content of immunoreactive somatostatin (SRIF) or the response to a 48-h exposure to forskolin (10 microM). Dex induction of NPY accumulation was a saturable function of the Dex concentration (maximal at 20 nM), and it was completely inhibited by RU486, a glucocorticoid/progesterone receptor antagonist; neither progesterone, 17 beta-estradiol, nor testosterone altered aggregate/medium NPY contents. Protein/DNA contents of the aggregates were either unaffected or slightly reduced by Dex. Thus, 1) Dex stimulates the accumulation of immunoreactive NPY, but not SRIF, by cultured fetal brain cells; 2) this effect requires a continuous 8-12 days of exposure to Dex during a late developmental stage in culture; 3) Dex does not potentiate or attenuate forskolin action on the NPY neuron; and 4) Dex action appears to be mediated by the glucocorticoid receptor. These results are consistent with glucocorticoid induction of production and/or decreased intracellular degradation of NPY, and with glucocorticoids regulating the NPY neuron in the perinatal brain in a developmental age-dependent manner.
神经肽Y（NPY）和糖皮质激素受体在大脑中的许多神经元中共同表达。我们探讨了以下问题：糖皮质激素是否调节培养的胎鼠脑细胞中免疫反应性（IR）NPY的积累和/或分泌？如果是，这种作用是否依赖于发育阶段？将从17日龄胎儿的下丘脑 - 嗅结节获得的解离细胞形成的聚集体在无血清培养基中培养23天。在第23天，聚集体中NPY含量为6 ng/瓶，分泌量（最后2天）约为12 ng/24小时。在第0 - 23天暴露于地塞米松（Dex；20 nM）导致聚集体中NPY含量增加1.9倍，而NPY分泌未改变。当Dex暴露限于第12 - 23天、16 - 23天、19 - 23天或21 - 23天时，只有12至23天的暴露诱导NPY积累，且其效果与0至23天的暴露相同。Dex诱导的NPY含量增加在4天或更长时间的延迟期后明显。当在第0 - 12天进行Dex暴露时，第12天或23天聚集体中NPY含量未改变。这些处理均未改变免疫反应性生长抑素（SRIF）的聚集体/培养基含量或对48小时暴露于福斯可林（10 microM）的反应。Dex诱导的NPY积累是Dex浓度的饱和函数（在20 nM时最大），并且被糖皮质激素/孕酮受体拮抗剂RU486完全抑制；孕酮、17β - 雌二醇或睾酮均未改变聚集体/培养基中NPY的含量。Dex对聚集体的蛋白质/DNA含量要么没有影响，要么使其略有降低。因此，1）Dex刺激培养的胎脑细胞积累免疫反应性NPY，但不刺激SRIF；2）这种作用需要在培养的后期发育阶段连续8 - 12天暴露于Dex；3）Dex不增强或减弱福斯可林对NPY神经元的作用；4）Dex的作用似乎由糖皮质激素受体介导。这些结果与糖皮质激素诱导NPY的产生和/或减少其细胞内降解一致，并且与糖皮质激素以发育年龄依赖性方式调节围产期大脑中的NPY神经元一致。
