Shifren J L, Mesiano S, Taylor R N, Ferrara N, Jaffe R B
Reproductive Endocrinology Center, Department of Obstetrics, Gynecology, and Reproductive Sciences, University of California, San Francisco 94143-0556, USA.
J Clin Endocrinol Metab. 1998 Apr;83(4):1342-7. doi: 10.1210/jcem.83.4.4730.
The human adrenal cortex has a complex vasculature that is essential for growth, organ maintenance, and access of secreted hormones to the circulation. Growth and function of the adrenal cortex are regulated by corticotropin (ACTH), the actions of which are in part mediated by locally produced growth factors. As cortical growth and vascularization must increase in a coordinated manner, we hypothesized that ACTH also influences adrenal cortical angiogenesis by stimulating the local expression of specific angiogenic factors. Vascular endothelial growth factor (VEGF) is a potent endothelial cell-specific angiogenic peptide, the expression of which has been detected in adrenal cortical cells. Therefore, we examined the localization of VEGF expression in the midgestation (16-20 weeks) human fetal adrenal cortex and determined whether VEGF expression and secretion by isolated human fetal adrenal cortical cells are regulated by ACTH. By immunohistochemical analysis, strong cytoplasmic staining for VEGF was detected in scattered clusters of fetal zone (inner cortical compartment) cells. In contrast, cells in the outer, definitive zone of the cortex stained only weakly for VEGF. The predominant staining for VEGF in the fetal zone correlated with the extensive vasculature of this zone as detected by immunohistochemical staining for von Willebrand factor, which is specific for endothelial cells. In primary cultures of human fetal adrenal cortical cells, ACTH (1 nmol/L) and forskolin (10 micromol/L) increased the abundance of messenger ribonucleic acid transcripts encoding VEGF, as assessed by Northern and slot blot analyses. The stimulatory effect of ACTH and forskolin on VEGF gene expression occurred within 2 h of agonist exposure and persisted for at least 24 h. ACTH and forskolin also increased VEGF protein secretion by fetal adrenal cortical cells, as assessed by enzyme-linked immunosorbent assay for VEGF in fetal adrenal cortical cell-conditioned medium. A significant (P < 0.05) increase in VEGF secretion was detected as early as 8 h after ACTH or forskolin treatment. By 24 h after the addition of ACTH or forskolin, VEGF secreted from isolated human fetal adrenal cells was increased 5- to 6-fold. These data demonstrate that the human fetal adrenal cortex, particularly the cells of the inner fetal zone, express VEGF and that VEGF expression and secretion by these cells are directly regulated by ACTH and the activation of adenylate cyclase. Thus, VEGF may be a local regulator of adrenal cortical angiogenesis and an important mediator of the tropic action of ACTH, ensuring the coordination of ACTH-stimulated cortical growth and vascularization.
人类肾上腺皮质具有复杂的脉管系统，这对于其生长、器官维持以及分泌的激素进入循环至关重要。肾上腺皮质的生长和功能受促肾上腺皮质激素（ACTH）调节，其作用部分由局部产生的生长因子介导。由于皮质生长和血管生成必须以协调的方式增加，我们推测ACTH还通过刺激特定血管生成因子的局部表达来影响肾上腺皮质血管生成。血管内皮生长因子（VEGF）是一种强效的内皮细胞特异性血管生成肽，在肾上腺皮质细胞中已检测到其表达。因此，我们研究了妊娠中期（16 - 20周）人类胎儿肾上腺皮质中VEGF表达的定位，并确定分离的人类胎儿肾上腺皮质细胞中VEGF的表达和分泌是否受ACTH调节。通过免疫组织化学分析，在胎儿带（皮质内区）细胞的散在簇中检测到VEGF的强细胞质染色。相比之下，皮质外层确定区的细胞VEGF染色较弱。胎儿带中VEGF的主要染色与该区域广泛的脉管系统相关，这通过针对内皮细胞特异性的血管性血友病因子的免疫组织化学染色检测到。在人类胎儿肾上腺皮质细胞的原代培养中，通过Northern印迹和狭缝印迹分析评估，ACTH（1 nmol/L）和福斯可林（10 μmol/L）增加了编码VEGF的信使核糖核酸转录本的丰度。ACTH和福斯可林对VEGF基因表达的刺激作用在激动剂暴露后2小时内出现，并持续至少24小时。通过对胎儿肾上腺皮质细胞条件培养基中VEGF的酶联免疫吸附测定评估，ACTH和福斯可林还增加了胎儿肾上腺皮质细胞的VEGF蛋白分泌。早在ACTH或福斯可林处理后8小时就检测到VEGF分泌有显著（P < 0.05）增加。在添加ACTH或福斯可林后24小时，分离的人类胎儿肾上腺细胞分泌的VEGF增加了5至6倍。这些数据表明，人类胎儿肾上腺皮质，特别是胎儿内带的细胞，表达VEGF，并且这些细胞中VEGF的表达和分泌直接受ACTH和腺苷酸环化酶的激活调节。因此，VEGF可能是肾上腺皮质血管生成的局部调节因子，也是ACTH促 tropic作用的重要介质，确保ACTH刺激的皮质生长和血管生成的协调。
