Lara H E, Hill D F, Katz K H, Ojeda S R
Division of Neuroscience, Oregon Regional Primate Research Center, Beaverton 97006.
Endocrinology. 1990 Jan;126(1):357-63. doi: 10.1210/endo-126-1-357.
The rat ovary is innervated by sympathetic nerve fibers. Since the development and survival of peripheral sympathetic neurons innervating nonreproductive organs have been shown to depend on the production of nerve growth factor (NGF) by the innervated tissues, the present experiments were undertaken to determine if the immature rat ovary has the capability of synthesizing NGF. Blot hybridization of ovarian polyadenylated RNA (A+-RNA) to a NGF cRNA probe revealed the presence of a 1.3- to 1.4-kilobase (kb) mRNA species similar to mature NGF mRNA detected in mouse submaxillary gland, a source rich in NGF. Quantitation of NGF protein by a sensitive and specific two-site enzyme immunoassay demonstrated the presence of NGF in juvenile ovaries at levels comparable to those found in other sympathetically innervated tissues. Neither denervation of the ovary nor treatment with gonadotropins (hCG and FSH) or somatomammotropins (PRL and GH) affected the levels of NGF mRNA. However, denervation significantly increased NGF levels, suggesting that, as in other target tissues, denervation prevents the retrograde transport of NGF by the sympathetic terminals and leads to accumulation of the protein at its site of production. It is concluded that 1) the developing ovary is able to both transcribe the NGF gene and translate its mRNA into NGF protein; and 2) the NGF content in the ovary is regulated by its innervation. The results provide the biochemical basis for the concept, elaborated in the companion paper, that NGF through its trophic actions on ovarian sympathetic neurons contributes to the regulation of ovarian development and, hence, to the acquisition of female reproductive capacity.
大鼠卵巢受交感神经纤维支配。由于支配非生殖器官的外周交感神经元的发育和存活已被证明依赖于受支配组织产生的神经生长因子（NGF），因此进行了本实验以确定未成熟大鼠卵巢是否具有合成NGF的能力。用NGF cRNA探针与卵巢多聚腺苷酸化RNA（A + -RNA）进行印迹杂交，结果显示存在一种1.3至1.4千碱基（kb）的mRNA种类，类似于在富含NGF的小鼠颌下腺中检测到的成熟NGF mRNA。通过灵敏且特异的双位点酶免疫测定法定量NGF蛋白，结果表明幼年卵巢中存在NGF，其水平与在其他受交感神经支配的组织中发现的水平相当。卵巢去神经支配以及用促性腺激素（hCG和FSH）或促生长激素（PRL和GH）处理均未影响NGF mRNA的水平。然而，去神经支配显著增加了NGF水平，这表明，与其他靶组织一样，去神经支配可阻止交感神经末梢对NGF的逆行运输，并导致该蛋白在其产生部位积累。得出以下结论：1）发育中的卵巢能够转录NGF基因并将其mRNA翻译成NGF蛋白；2）卵巢中的NGF含量受其神经支配的调节。这些结果为在配套论文中阐述的概念提供了生化基础，即NGF通过其对卵巢交感神经元的营养作用有助于调节卵巢发育，从而有助于获得雌性生殖能力。
