Tandon P, Gupta M L, Barthwal J P, Gupta T K, Parmar S S, Bhargava K P
Steroids. 1983 Sep;42(3):231-9. doi: 10.1016/0039-128x(83)90035-1.
The effect of medroxyprogesterone acetate (MPA) on brain monoamine levels and monoamine oxidase (MAO) activity was studied in adult, healthy, non-pregnant female rats. MpA was injected in a single dose of 100 mg/kg i.m. Dopamine (DA), noradrenaline (NA), 5-hydroxytryptamine (5-HT) levels and MAO activity were estimated fluorometrically in rat brian. No change in DA, NA, 5-HT or MAO activity was observed after 7 days of MPA treatment while a significant decrease in DA levels along with a significant increase in MAO activity was observed after 21 days of MPA treatment. However, there was no change in NA and 5-HT levels after 21 days of MPA administration. The selective reduction of DA by MPA could be due to an increase in MAO-B activity. MPA does not appear to increase MAO-A activity because neither of the specific substrates (NA and 5-HT) of MAO-A was found to be decreased inspite of the increase in MAO activity as estimated by the kynuramine method. These findings suggest the importance of MAO-B also in DA metabolism in rat brain.
在成年、健康、未怀孕的雌性大鼠中研究了醋酸甲羟孕酮（MPA）对脑单胺水平和单胺氧化酶（MAO）活性的影响。以100mg/kg的单次剂量肌肉注射MPA。采用荧光法测定大鼠脑中多巴胺（DA）、去甲肾上腺素（NA）、5-羟色胺（5-HT）水平和MAO活性。MPA治疗7天后，未观察到DA、NA、5-HT或MAO活性的变化，而MPA治疗21天后，观察到DA水平显著降低，同时MAO活性显著增加。然而，MPA给药21天后，NA和5-HT水平没有变化。MPA对DA的选择性降低可能是由于MAO-B活性增加所致。MPA似乎不会增加MAO-A活性，因为尽管用犬尿胺法估计MAO活性增加，但未发现MAO-A的特异性底物（NA和5-HT）减少。这些发现表明MAO-B在大鼠脑DA代谢中也很重要。
