Gangula P R, Dong Y L, Yallampalli C
Department of Obstetrics and Gynecology, The University of Texas Medical Branch, Galveston 77555, USA.
Hum Reprod. 1997 Mar;12(3):561-8. doi: 10.1093/humrep/12.3.561.
We examined if rat myometrial cells in culture generate nitric oxide (NO) and express various isoforms of NO synthase (NOS). Myometrial cells isolated from rats on day 18 of gestation were incubated with various stimulators and inhibitors of NOS for 24 and 48 h, and NO production was evaluated by measuring nitrites in the media and NOS proteins in the cell lysates. NO was produced by myometrial cells and its production inhibited by N(G)-methyl-L-arginine (L-NMMA). This inhibition was reversed by L-arginine (3 mM). Interleukin-1beta (IL-1beta) significantly stimulated NO production, in a dose-dependent manner. The IL-1beta-stimulated NO production was inhibited by the NOS inhibitor, L-NMMA, whose effects were reversed by L-arginine. Abundant NOS III protein was detectable in freshly isolated myometrial cells, and this was maintained in culture in the presence of fetal bovine serum (FBS; 10%). In the absence of FBS, NOS III levels decreased significantly (by 90%) within 24 h. In contrast, NOS I and NOS II proteins were undetectable in freshly isolated muscle cells and in cells cultured without IL-1beta. However, NOS II protein in these cells was induced by IL-1beta. Thus, NO is produced by myometrial cells through the NOS III isoform, and the myometrial NO may be important in maintaining uterine quiescence during pregnancy.
我们研究了培养的大鼠子宫肌层细胞是否产生一氧化氮（NO）并表达一氧化氮合酶（NOS）的各种同工型。从妊娠第18天的大鼠分离出的子宫肌层细胞与NOS的各种刺激剂和抑制剂一起孵育24和48小时，并通过测量培养基中的亚硝酸盐和细胞裂解物中的NOS蛋白来评估NO的产生。子宫肌层细胞产生NO，其产生受到N（G）-甲基-L-精氨酸（L-NMMA）的抑制。这种抑制作用可被L-精氨酸（3 mM）逆转。白细胞介素-1β（IL-1β）以剂量依赖性方式显著刺激NO的产生。IL-1β刺激的NO产生受到NOS抑制剂L-NMMA的抑制，其作用可被L-精氨酸逆转。在新鲜分离的子宫肌层细胞中可检测到丰富的NOS III蛋白，并且在存在胎牛血清（FBS；10%）的情况下在培养中得以维持。在没有FBS的情况下，NOS III水平在24小时内显著下降（90%）。相比之下，在新鲜分离的肌肉细胞和未用IL-1β培养的细胞中未检测到NOS I和NOS II蛋白。然而，这些细胞中的NOS II蛋白可被IL-1β诱导。因此，子宫肌层细胞通过NOS III同工型产生NO，并且子宫肌层的NO在维持妊娠期间子宫静息状态中可能很重要。
