Dong Y L, Gangula P R, Yallampalli C
Department of Obstetrics and Gynecology, University of Texas Medical Branch, Galveston 77555-1062, USA.
J Reprod Fertil. 1996 Jul;107(2):249-54. doi: 10.1530/jrf.0.1070249.
Production of nitric oxide in the uterus is increased during pregnancy and decreased during delivery. In this study the isoform of nitric oxide synthase which may be responsible for the changes in nitric oxide production was investigated in relation to pregnancy and delivery. Monoclonal antibodies were used to measure changes in neuronal nitric oxide synthase (NOS I), macrophage nitric oxide synthase (NOS II) and endothelial cell nitric oxide synthase (NOS III) protein in the rat uterus by densitometric scanning of specific bands. Results show that: (1) NOS II protein concentrations in the uterus were substantially increased during pregnancy and were decreased during delivery, both at term and preterm (induced by RU486); (2) NOS III protein was present at all stages examined but the concentrations were unchanged; (3) NOS I was present in the rat uterus during the nonpregnant stage but not during pregnancy and delivery. The changes in uterine NOS II protein concentrations during pregnancy and delivery were further confirmed by the changes in the Ca(2+)-independent, but not Ca(2+)-dependent, nitric oxide synthase activity. Therefore, an increase in NOS II, thus in nitric oxide production during pregnancy, may play a role in maintaining uterine quiescence.
孕期子宫中一氧化氮的生成增加，分娩时减少。在本研究中，研究了可能与一氧化氮生成变化有关的一氧化氮合酶同工型与妊娠和分娩的关系。通过对特定条带进行光密度扫描，使用单克隆抗体来测量大鼠子宫中神经元型一氧化氮合酶（NOS I）、巨噬细胞型一氧化氮合酶（NOS II）和内皮细胞型一氧化氮合酶（NOS III）蛋白的变化。结果表明：（1）子宫中NOS II蛋白浓度在孕期显著增加，在足月和早产（由RU486诱导）分娩时均降低；（2）在所有检查阶段均存在NOS III蛋白，但其浓度未发生变化；（3）在非妊娠阶段大鼠子宫中存在NOS I，但在妊娠和分娩期间不存在。子宫NOS II蛋白浓度在妊娠和分娩期间的变化通过不依赖钙但不依赖钙的一氧化氮合酶活性变化得到进一步证实。因此，孕期NOS II增加，进而一氧化氮生成增加，可能在维持子宫静息中起作用。
