| Summary: | 碩士 === 國立陽明大學 === 生理學研究所 === 92 === Steroids have been known to be involved in various physiological responses with a primary focus on the genomic aspects of action. Recently, increasing evidence for rapid, nongenomic steroid effects has been demonstrated for virtually all groups of steroids. As judged from the time scale, the classic steroid receptor pathway does not mediate the effects on ion fluxes. In our previous study, progesterone had nongenomic effects on intracellular Ca2+ increase [Ca2+]i and pH [pHi] decrease in T cells. Therefore, the aim of this study was to investigate whether testosterone, estradiol, and glucocorticoid had similar nongenomic effects as progesterone and were these steroids affect cytokine secretion and proliferation in human T cells. [Ca2+]i and pHi responses were respectively measured using the fluorescent dyes, fura-2 and BCECF in T cells. The IL-2, IL-4 secretion were measured by ELISA. Proliferation was determined by [3H]-thymidine incorporation into PHA-stimulated T cells. The changes of cell cycle distribution on PHA-stimulated T cells by various steroid were detected by flow cytometry using fluorescent dye, propidium iodide. Our results indicated that (1) progesterone, testosterone, and estradiol resulted an elevation of [Ca2+]i within 5 min, while glucocorticoid didn’t; (2) progesterone, hydrocortisone, and dexamethasone resulted in an decrease of pHi within 10 min, while testosterone and estradiol didn’t; (3) the acidification was due to the inhibition of Na+/H+-exchanger (NHE) activity by progesterone, glucocorticoid and dexamethasone and Ki= 6.32 μM, Ki= 64.18 nM, and Ki= 7.58 nM respectively, but inactive steroid of progesterone－20□-hydroxyprogesterone(20α-OHP) didn’t; (4) PHA stimulated the secretions in IL-2, IL-4, but progesterone, testosterone, estradiol, or glucocorticoid could significantly suppress PHA-induced IL-2 secretions in T cells; progesterone, estradiol, or glucocorticoid also significantly suppress PHA-induced IL-4 secretions in T cells, except testosterone; (5) the administration of progesterone, testosterone, estradiol, or glucocorticoid could suppress PHA-induced [3H]-thymidine uptake into T cells; (6) progesterone and hydrocortisone exhibited more effect on suppression PHA-induced [3H]-thymidine uptake when addition them 72 h after PHA stimulation; (7) the nongenomic effects of P4-BSA were similar to progesterone in T cells; (8) progesterone, testosterone, estradiol, or glucocorticoid could suppress cell cycle distribution from G0/G1 to S phase in PHA-activated T cells. In conclusion, steroid hormones (progesterone, estradiol, testosterone, glucocorticoid) exert nongenomic effects in T cells. These nongenomic effects also affected the genomic effect such as inhibited the PHA-induced cytokine secretion, cell cycle distribution, and cell proliferation. In addition, the nongenomic effects of progesterone were demonstrated to mediate by the membrane receptor in T cells.
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