Chang Ling-Ling, Wun Alfred Wan-Song, Hung Chien-Te, Hsia Shih-Min, Chiang Wenchang, Wang Paulus S
Department of Chemical Engineering, Chinese Culture University, Shih-Lin, Taipei, Taiwan, Republic of China.
Naunyn Schmiedebergs Arch Pharmacol. 2006 Nov;374(2):141-52. doi: 10.1007/s00210-006-0094-x. Epub 2006 Sep 21.
Adlay is a grass crop which has been used in traditional Chinese medicine and also as a nourishing food. It has been shown to posses anti-allergic, antimutagenic and hypolipemic effects. However, the effects and action mechanisms of crude adlay hull acetone extract (AHA) on adrenal zona fasciculata-reticularis (ZFR) cells are still unclear. This study explored the effects of AHA on corticosterone release. ZFR cells were incubated with AHA in the presence or absence of adrenocorticotropin (ACTH), 8-bromo-cyclic 3': 5'- adenosine monophosphate (8-Br-cAMP), forskolin (FSK), 25-hydroxy cholesterol (25-OH-cholesterol), pregnenolone, progesterone or deoxycorticosterone. The concentrations of corticosterone or pregnenolone in the media were measured by radioimmunoassay (RIA). The cells were used to measure the expression of steroidogenic acute regulatory (StAR) protein by Western blot. The present data demonstrated that: (1) AHA inhibited ACTH-, 8-Br-cAMP-, forskolin-, 25-OH-cholesterol-, pregnenolone-, progesterone- or deoxycorticosterone-stimulated corticosterone release; (2) AHA (800 microg/ml) caused more pregnenolone release in control group, but not in 25-OH-cholesterol, trilostane or 25-OH-cholesterol+trilostane group; (3) kinetic study showed an uncompetitive inhibition model of AHA to P450 side chain cleavage enzyme (P450scc); (4) kinetic study showed a noncompetitive inhibition model of AHA to 11beta-hydroxylase; and (5) AHA inhibited the expression of StAR protein. These results suggest that AHA acts directly upon rat ZFR cells to diminish corticosterone release. These results indicate the inhibitory mechanism of AHA mediates through an inhibition of the activities of the post-cAMP corticosterone synthesis enzymes, i.e. 3beta-HSD, 21-hydroxylase, 11beta-hydroxylase, and inhibition of StAR protein expression.
薏仁是一种草本作物，已被用于传统中药，也作为滋补食品。研究表明，薏仁具有抗过敏、抗诱变和降血脂作用。然而，薏仁粗壳丙酮提取物（AHA）对肾上腺束状带-网状带（ZFR）细胞的作用及其机制仍不清楚。本研究探讨了AHA对皮质酮释放的影响。在有或无促肾上腺皮质激素（ACTH）、8-溴环3':5'-腺苷单磷酸（8-Br-cAMP）、福司可林（FSK）、25-羟基胆固醇（25-OH-胆固醇）、孕烯醇酮、孕酮或脱氧皮质酮存在的情况下，将ZFR细胞与AHA一起孵育。通过放射免疫分析（RIA）测定培养基中皮质酮或孕烯醇酮的浓度。用细胞通过蛋白质印迹法测量类固醇生成急性调节（StAR）蛋白的表达。目前的数据表明：（1）AHA抑制ACTH、8-Br-cAMP、福司可林、25-OH-胆固醇、孕烯醇酮、孕酮或脱氧皮质酮刺激的皮质酮释放；（2）AHA（800微克/毫升）在对照组中导致更多的孕烯醇酮释放，但在25-OH-胆固醇、曲洛司坦或25-OH-胆固醇+曲洛司坦组中则不然；（3）动力学研究表明AHA对P450侧链裂解酶（P450scc）具有非竞争性抑制模型；（4）动力学研究表明AHA对11β-羟化酶具有非竞争性抑制模型；（5）AHA抑制StAR蛋白的表达。这些结果表明，AHA直接作用于大鼠ZFR细胞以减少皮质酮释放。这些结果表明，AHA的抑制机制是通过抑制cAMP后皮质酮合成酶即3β-羟类固醇脱氢酶、21-羟化酶、11β-羟化酶的活性以及抑制StAR蛋白表达来介导的。
