Glucocorticoids regulate pituitary growth hormone secretagogue receptor gene expression.
Glucocorticoids regulate pituitary growth hormone secretagogue receptor gene expression.
复制标题
糖皮质激素调节垂体生长激素促分泌素受体基因表达。
DOI：
10.1046/j.1365-2826.2000.00446.x
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发表时间：
2000
影响因子：
3.2
通讯作者：
Wakabayashi,I
中科院分区：
文献类型：
--
作者：
Tamura,H;Kamegai,J;Sugihara,H;Kineman,RD;Frohman,LA;Wakabayashi,I
糖皮质激素通过调节下丘脑和垂体功能调节生长激素（GH）的分泌。在垂体水平，糖皮质激素增加GH和GH释放激素受体（GHRH‐R）基因的表达。为了测试糖皮质激素是否也可能调节垂体中最近发现的GH分泌素（GHS）受体GHS‐R的表达；取成年雄性大鼠进行肾上腺切除或假手术，给予合成糖皮质激素（地塞米松，200µg/d）或载药治疗8 d。逆转录聚合酶链反应（RT‐PCR）检测垂体GHS‐R mRNA水平。肾上腺切除术使假手术大鼠垂体GHS - R mRNA减少45% （P < 0.05）。地塞米松使假手术大鼠和去肾上腺大鼠GHS - R mRNA水平分别升高（199±24% （P < 0.05）和369±48% (P < 0.01)）。将地塞米松添加到原代大鼠垂体细胞培养物中，以剂量和时间依赖的方式增加GHS - R mRNA水平，而转录抑制剂放线菌素D完全阻断地塞米松的刺激作用。综上所述，这些结果表明糖皮质激素通过刺激GHS - R基因转录直接增加垂体GHS - R mRNA水平。
Glucocorticoids regulate growth hormone (GH) secretion by modulating both hypothalamic and pituitary function. At the level of the pituitary, glucocorticoids increase GH and GH‐releasing hormone receptor (GHRH‐R) gene expression. To test if glucocorticoids might also regulate the pituitary expression of the recently identified GH secretagogue (GHS) receptor, GHS‐R; adult male rats were adrenalectomized or sham operated, and treated with the synthetic glucocorticoid (dexamethasone, 200 µg/day) or vehicle for 8 days. Pituitary GHS‐R mRNA levels were assessed by reverse transcriptase polymerase chain reaction (RT‐PCR). Adrenalectomy decreased pituitary GHS‐R mRNA to 45% of vehicle‐treated, sham‐operated rats (P < 0.05). Administration of dexamethasone increased GHS‐R mRNA levels in sham‐operated as well as in adrenalectomized rats (199 ± 24% (P < 0.05) and 369 ± 48% (P < 0.01) of vehicle‐treated controls). Addition of dexamethasone to primary rat pituitary cell cultures increased GHS‐R mRNA levels in a dose‐ and time‐dependent manner while the transcriptional inhibitor, actinomycin D, completely blocked the stimulatory action of dexamethasone. Taken together, these results suggest glucocorticoids directly increase pituitary GHS‐R mRNA levels by stimulating GHS‐R gene transcription.