Anouar Y, Benie T, De Monti M, Counis R, Duval J
Laboratoire d'Endocrinologie Moléculaire, Centre National de la Recherche Scientifique, Unité de Recherche Associée 256, Rennes, France.
Endocrinology. 1991 Nov;129(5):2393-9. doi: 10.1210/endo-129-5-2393.
Estradiol (E2) effects on the pituitary and adrenal secretogranin II (SgII) and chromogranin A (CgA) proteins and mRNA levels were analyzed in the adult female rat. Animals were ovariectomized or sham-operated for 2 weeks and then daily injected with various doses of 17 beta-E2 (from 5-100 micrograms) for the following week. SgII and CgA levels were determined by Western blot analysis using two specific antisera. Messenger RNA (mRNA) levels were measured by RNA slot blot analysis using specific cDNA probes. Simultaneously, pituitary LH content and gonadotropin subunit (LH beta, FSH beta, alpha) mRNAs were quantified. Ovariectomy promoted a significant increase in pituitary SgII and CgA proteins (2-fold vs. sham-operated animals, P less than 0.01) and a concomitant rise in their mRNA levels (2.5-fold and 4.5-fold for SgII mRNA and CgA mRNA, respectively, P less than 0.01). In the same animals LH beta, FSH beta, and alpha-subunit mRNA levels increased by 20-, 12-, and 6-fold, respectively. Estrogen replacement resulted in a parallel decrease of CgA and LH beta mRNA to the control values, starting from the lowest steroid dose (5 micrograms). The SgII mRNA decrease was initiated only with a higher concentration of E2 (10 micrograms), as was that of alpha-subunit mRNA; yet, the SgII mRNA level remained significantly higher than in the control pituitary, even with the highest steroid dose (P less than 0.05) at variance with the alpha-mRNA level. Concerning protein concentration, the postcastration increase in CgA was fully reverted with 10 micrograms E2 while that of SgII remained unaffected, as was the pituitary LH content. In the adrenal gland, neither the ovariectomy nor the E2 therapy altered significantly the SgII or CgA protein and mRNA concentrations. We conclude that, in rats, 1) ovarian factors regulate the pituitary SgII and CgA protein and mRNA steady-state levels while such factors are inefficient in the adrenal gland, 2) CgA and LH beta mRNAs exhibit the same sensitivity to E2 while SgII and alpha-subunit mRNAs appear less sensitive, and 3) SgII and LH pituitary contents present a similar pattern of variations when the estrogenic status of the animal is modified.
在成年雌性大鼠中分析了雌二醇（E2）对垂体和肾上腺分泌粒蛋白II（SgII）及嗜铬粒蛋白A（CgA）蛋白和mRNA水平的影响。动物接受卵巢切除或假手术2周，然后在接下来的一周每天注射不同剂量的17β-E2（5 - 100微克）。使用两种特异性抗血清通过蛋白质印迹分析测定SgII和CgA水平。使用特异性cDNA探针通过RNA斑点印迹分析测量信使RNA（mRNA）水平。同时，对垂体LH含量和促性腺激素亚基（LHβ、FSHβ、α）mRNA进行定量。卵巢切除导致垂体SgII和CgA蛋白显著增加（与假手术动物相比增加2倍，P < 0.01），同时其mRNA水平相应升高（SgII mRNA和CgA mRNA分别增加2.5倍和4.5倍，P < 0.01）。在同一批动物中，LHβ、FSHβ和α亚基mRNA水平分别增加了20倍、12倍和6倍。从最低剂量的类固醇（5微克）开始，雌激素替代导致CgA和LHβ mRNA平行下降至对照值。SgII mRNA的下降仅在较高浓度的E2（10微克）时开始，α亚基mRNA也是如此；然而，即使在最高剂量的类固醇作用下，SgII mRNA水平仍显著高于对照垂体（P < 0.05），这与α亚基mRNA水平不同。关于蛋白质浓度，去势后CgA的增加在给予10微克E2时完全恢复，而SgII的增加以及垂体LH含量均未受影响。在肾上腺中，卵巢切除和E2治疗均未显著改变SgII或CgA蛋白及mRNA浓度。我们得出结论，在大鼠中，1）卵巢因素调节垂体SgII和CgA蛋白及mRNA的稳态水平，而这些因素在肾上腺中无效；2）CgA和LHβ mRNA对E2表现出相同的敏感性，而SgII和α亚基mRNA似乎敏感性较低；3）当动物的雌激素状态改变时，SgII和LH垂体含量呈现相似的变化模式。
