Lustig R H, Sudol M, Pfaff D W, Federoff H J
Laboratory of Neurobiology and Behavior, Rockefeller University, New York, NY 10021.
Brain Res Mol Brain Res. 1991 Sep;11(2):125-32. doi: 10.1016/0169-328x(91)90114-d.
In addition to effects on brain protein synthesis, neurotransmitter release, and electrophysiology, estrogens alter neurite outgrowth and synaptogenesis. This study examined in the adult rat the effects of estrogen and sex on the expression of the GAP-43 gene; encoding a phosphoprotein structurally and physiologically linked to these two processes in the rat CNS. Ovariectomized (OVX) rats were injected with vehicle or estrogen, or male and female rats were either gonadectomized or left intact. Brains were dissected to obtain ventromedial hypothalamus (VMH), posterior hypothalamus (PH), or frontal cortex (CTX). Total RNA from these areas were extracted, and slot-blots of equal masses of total RNA were hybridized to 32P-labeled cDNAs for GAP-43 and beta-actin, and also to synthetic poly-dT. Resultant autoradiograms were scanned by laser densitometry, quantitated, and ratios of the gray scale generated by each probe were compared between experimental groups. GAP-43 mRNA expression, when compared to expression of either beta-actin mRNA or total poly(A)-containing RNA (poly(A) RNA), was higher in VMH and PH as compared to CTX. Estrogen treatment of OVX rats resulted in a 48-74% increase in GAP-43 mRNA levels in the VMH--in one experiment, this increase was noted after 2 h of estradiol treatment, and in another after 3 days of estradiol benzoate treatment; but PH and CTX were unaffected by either estrogen regimen. Conversely, ovariectomy of intact rats decreased GAP-43 mRNA expression by 45% in the VMH, but not in the CTX.(ABSTRACT TRUNCATED AT 250 WORDS)
除了对脑蛋白质合成、神经递质释放和电生理学产生影响外，雌激素还会改变神经突生长和突触形成。本研究在成年大鼠中检测了雌激素和性别对GAP - 43基因表达的影响；该基因编码一种磷蛋白，在大鼠中枢神经系统中，其结构和生理功能与这两个过程相关。给去卵巢（OVX）大鼠注射溶剂或雌激素，或者对雄性和雌性大鼠进行性腺切除或保持完整。解剖大脑以获取腹内侧下丘脑（VMH）、下丘脑后部（PH）或额叶皮质（CTX）。提取这些区域的总RNA，将等量总RNA的狭缝印迹与GAP - 43和β -肌动蛋白的32P标记cDNA杂交，也与合成的聚dT杂交。通过激光密度测定法扫描所得放射自显影片，进行定量，并比较各实验组中每个探针产生的灰度比值。与β -肌动蛋白mRNA或总含聚腺苷酸RNA（poly(A) RNA）的表达相比，VMH和PH中的GAP - 43 mRNA表达高于CTX。对OVX大鼠进行雌激素处理导致VMH中GAP - 43 mRNA水平增加48 - 74%——在一项实验中，雌二醇处理2小时后就观察到这种增加，在另一项实验中，苯甲酸雌二醇处理3天后观察到增加；但PH和CTX不受任何一种雌激素处理方案的影响。相反，对完整大鼠进行去卵巢手术会使VMH中GAP - 43 mRNA表达降低45%，但CTX中不受影响。（摘要截短于250字）
