糖皮质激素对大鼠下丘脑-垂体-肾上腺轴Ca^(2+)/CaMPKⅡ的影响

Effects of glucocorticoid on Ca^(2+)/CaMPKⅡin hypothalamus-pituitary-adrenal axis of rats

目的研究糖皮质激素醋酸可的松对大鼠下丘脑-垂体-肾上腺轴(HPAA)游离钙(Ca2+)及钙调素依赖的蛋白激酶Ⅱ(CaMPKⅡ)的影响。方法用流式细胞仪及钙荧光探针Flou-3/AM来测定细胞中的Ca2+,通过液体闪烁仪测定γ-32P-ATP参入反应底物的摩尔数,用来表示蛋白激酶的活性。结果醋酸可的松组大鼠下丘脑细胞[Ca2+]i荧光强度为129.32±17.74,显著高于对照组60.65±10.64,P<0.05。而醋酸可的松组大鼠下丘脑、肾上腺组织中CaMPKⅡ活性分别为14.07+3.15和3.87+1.47(nmolPi.min-1.mg-1protein),与对照组的7.91+3.2和2.23+0.52(nmolPi.min-1.mg-1protein)相比显著升高,差异有统计学意义,P<0.001。结论糖皮质激素对下丘脑-垂体-肾上腺轴的调控作用与Ca2+、CaMPKⅡ密切相关。

Objective To study the effect of glucocorticoid on Ca2＋/ CaMPK II in hypothalamus-pituitaryadrenal axis （HPAA） of rats.Methods [ Ca2＋ ] i of hypothalamus-pituitary-adrenal axis in rats were tested with flowcytometry by using [ Ca2＋] i fluorescent probe-Flou-3/AM . CaMPK II activities were measured by the incorporation mol of 32p from radiolabeled ATP into substrate autocamide 3 with liquid scintillation counter. Results The fluorescence intensity of [ Ca2＋] i in rat hypothalamic cells in cortisone acetate group （ 129.32 ± 17.74） were higher than that the control group （60.65 ±10.64） （P〈 0.05）. The activity of CaMPK II in the rat hypothalamus and adrenal tissues in cortisone acetate group （（ 14.07 ±14.07） and （3.87 ± 1.47） nmolPi. Min -i. mg-1 protein）, were significantly increased （P〈 0.001 ） compared with that （ （ 7.91±7.91 ） and （ 2.23 ±0.52） nmolPi. Min -1. mg-1 protein） in the control group. Conclusion Ca2＋ and CaMPK 1I were involved in the regulation of glucocorticoid on HPAA.