Effects of appetite regulating nuropeptides on somatotroph axis of cattle

本文详细介绍了牛腺垂体中食欲调节神经肽（食欲素：OX，甘丙氨酸：Gal，瘦素：Lep，神经肽Y: nero Y）对生长因子的表达和影响。在牛腺垂体中表达了pre - pro- ox mRNA和ox1受体（OX1R） mRNA，并测定了它们的部分DNA和氨基酸序列。oxa定位于PRL细胞中，OX1R也存在于相同的细胞类型中。然而，OX-A在腺垂体细胞原代培养中对GH和PRL的释放没有效果。ACTH细胞中存在Gal mRNA和免疫反应性Gal。Gal的表达主要由睾酮介导。产Gal细胞同时表达雄激素受体（AR）和雌激素受体（ER）。结果表明，ACTH细胞中Gal的表达受另一种类型腺垂体细胞中P450芳香化酶介导的睾酮来源雌激素的er结合信号的调节，因此，在腺垂体中表达了内源性Lap mRNA，免疫反应性Lep主要局限于GH细胞，但在少数PRL、TSH和GTH细胞中也有免疫反应。由于已知细胞因子在神经内分泌系统中发挥重要作用，我们详细研究了白细胞介素18 （IL-18）及其受体IL-18R在腺垂体细胞中的表达。IL-18 mRNA和免疫反应性IL-18在GH细胞中定位。测定了牛IL-18Rα的部分DNA序列，并在GH细胞中定位了免疫反应性IL-18Rα。这些发现提示IL-18可能以自分泌的方式参与生长激素的分泌或生长因子的分化。建立了表达IL-18和IL-18Rα并能长时间传代的牛腺垂体细胞系。本研究的新发现正以四篇出版物的形式向国际期刊投稿。

Expression and affects of appetite regulating nuropeptides (orexin : OX, Galanin : Gal, leptin : Lep, nuropeptide Y : nero Y) on somatotrophs were detailed in bovine adenohypophysis. Prepro-OX mRNA and OX1-receptor (OX1R) mRNA were expressed and their partial DNA and amino acid sequences were determined in bovine adenohypophysis. OX-A was localized in PRL cells and OX1R was also detected in the identical cell type. However, OX-A was not effective on the release of GH and PRL in the primary cultures of the adenohypophysial cells. Gal mRNA and immunoreactive Gal were localized in ACTH cells. The Gal expression was mainly mediated by testosterone. Gal producing cells also expressed both of androgen receptor (AR) and estrogen receptor (ER). It was demonstrated that the Gal expression in ACTH cells was regulated by ER-binding signals of estrogen derived from testosterone by P450 aromatase in another type cells of the adenohypophysis, so called, intracrinology fashion Lap mRNA were expressed in the adenohypophysis and immunoreactive Lep was mainly localized in GH cells although was immunoreactive in a small number of PRL, TSH and GTH cells. Since cytokines are known to exert important roles in nuroendocrine system, the expression of interleukin 18 (IL-18) and its receptor (IL-18R) in the adenohypophysial cells was examined in detail. IL-18 mRNA and immunoreactive IL-18 were localized in GH cells. The partial DNA sequence of bovine IL-18R α was determined and immunoreactive IL-18Rα was also localized in GH cells. These findings indicate that IL-18 may plays GH secretion or the differentiation of somatotrophs in autocrine fashion. Furthermore, bovine adenohypophysial cell line that presents IL-18 and IL-18Rα,and can passages for long time was established. New findings in the present study are ordering to submit international Journals as four publications.