胰岛素对糖皮质激素受体的调节作用

在人体白细胞培养基质中加入不同浓度的胰岛素,3h 和24h 后以[~3H]标记的地塞米松([~3H] Dex)特异结合力为指标,研究了胰岛素对糖皮质激素受体(GR)的抑制作用。在基质中分别加入 20mU/L(生理浓度),200mU/L(生理调节时最高血浓度)及2000mU/L(药理浓度),3h 后和不含胰岛素的对照值比,[~3H] Dex 的特异结合力分别减少23.3±10.0,32.2±13.2及54.3±9.2%(P>0.05,P>0.05及P<0.01;24h 后,和对照值相比,特异结合力分别减少43.5±19.0,56.1±20.7和80.2±15.5(P<0.05,P7<0.01,P<0.01)。胰岛素对 GR 特异结合力的抑制效应呈剂量和时间依赖性,它提示了胰岛素浓度在生理条件下对 GR 有紧张性调控作用。

REGULATORY EFFECT OF INSULIN ON GLUCOCORTICOID RECEPTOR IN HUMAN PERIPHERAL LEUKOCYTES

The regulatory effect of insulin on the specific binding power of glucocorticoid receptor (GR) of human leukocytes was assessed by the unoccupied receptor sites capable of combining with [3H] labelled dexamethasone measured at 3 and 24 h after incubation with various concentrations of insulin added to the medium. After 3 h incubation the specific binding power with [3H] Dex was decreased by 23.3 +/- 10.0, 32.2 +/- 13.2 and 54.3 +/- 9.2% (P greater than 0.05, P greater than 0.05 and P less than 0.01 as compared with the control value of 100 in the absence of insulin) respectively in the presence of 20 mU/L (physiological testing concentration), 200 mU/L (physiological upper limit) and 2,000 mU/L (pharmacological concentration) insulin in the incubation medium. After 24 h incubation the decrease of these values increased respectively to 43.5 +/- 19.0, 56.1 +/- 20.7 and 80.2 +/- 15.5 (P less than 0.05, P less than 0.01 and P less than 0.01 compared with control). Thus the inhibitory effect of insulin on the GR binding power is both dose- and time-dependent, which strongly suggests that GR is tonically controlled by insulin concentration change under physiological conditions.