二氢睾酮和其受体对雄性大鼠血小板激活、TXA_2/PGI_2平衡与细胞内钙离子浓度的调节

Effects of Dihydrotestosterone on ADP-induced Platelet Activation, Balance of TXA2/PGI2 and Intracellular Calcium Concentration in Male Rats.

目的研究生理剂量二氢睾酮(dihydrotestosterone,DHT)和其受体对雄性大鼠血小板激活、TXA2/PGI2平衡与细胞内钙离子浓度的调节。方法血浆睾酮(testosterone,T)应用Advia Centaur免疫检测系统测定(Bayer,Ger-many),血浆DHT应用酶联免疫试剂盒(ELISA kit)推荐方法检测。应用血小板聚集仪测定血小板聚集、血小板黏附仪测定血小板黏附。应用放免法测定TXB2和6-Keto-PGF1α。应用流式细胞仪测定血小板内钙离子浓度。结果去势雄性大鼠每日补充DHT(0.25mg/rat)使其DHT浓度达到生理水平,而且与氟他胺(flutamide)(每两日注射1次5mg/rat)联用不影响DHT浓度达到生理水平。DHT(2nM)显著抑制二磷酸腺苷(adenosine diphosphate,ADP)诱导的血小板的聚集、黏附。氟他胺预处理血小板之后,ADP诱导的血小板的聚集、黏附再次增加。去势雄性大鼠每日补充DHT(0.25mg/rat)降低TXB2和6-keto-PGF1α的比例,然而两日补充一次氟他胺(5mg/rat)再次增加TXB2和6-keto-PGF1α的比例。DHT(2nM)明显降低ADP诱导的血小板内钙离子浓度。然而,氟他胺预处理血小板之后ADP诱导的血小板内钙离子浓度再次增加。结论生理水平二氢睾酮介导其受体调节雄性大鼠ADP诱导的血小板聚集、黏附与其调节TXA2/PGI2平衡和血小板内钙离子浓度有关。

Objective The aim of our study is to assess the effects of androgen dihydrotestostosterone （DHT） and its receptor on ADP-induced platelet activation, balance of TXA2/PGI2 and intracellular calcium concentration in male rats. Methods Total plasma testosterone was measured using ADVIA Centaur immunoassay system, whereas DHT levels were measured using a DHT ELISA kit. Platelet aggregometer was used to measure platelet aggregation, and platelet adherometer was used to measure platelet adhesion. The contents of TXB2 and 6-Keto-PGF1α were assayed using radio-immunoassay kit. The intraplatelet free calcium concentrations were measured with fluo- 3/AM FCM assay. Results DHT replacement restored circulating DHT to physiological levels, without being altered by treatment with flutamide, pretreatment with DHT （2nM） significantly inhibited the platelet aggregation and adhesion induced by ,ADP. After PRP was pretreated with flutamide, ADP-induced platelet aggregation and adhesion increased again. After castration and DHT replacement, the ratio of both TXB2 and 6-keto-PGF1α obviously decreased. However, administration of flutamide to DHT treated castrated rats caused an increase in the proportions of both TXB2 and 6-keto-PGF1α again. DHT （2nM） replacement obviously reduced [ Ca^2＋]i. However, Pretreatment with flutamide and DHT （2nM）, [ Ca^2＋]i increase induced by ADP was observed once more. Conclusion DHT regulates ADP-induced plate- let aggregation and adhesion via its receptor, which is related to its modulation of balance of TXA2/PGI2 and intracellular calcium concentration in male rats.