Kaaja R, Are K
Department of Obstetrics and Gynecology Helsinki University Hospital, Finland.
Basic Res Cardiol. 1996 Jul-Aug;91(4):269-74. doi: 10.1007/BF00789298.
The role of hypophysis in cardiac growth, and in myocardial lactic dehydrogenase (LDH) isoenzyme adaptations to hypobaric hypoxia (9.5% O2) during 3 weeks was studied in four groups of hypophysectomized rats: one group received no hormone, and the second, third, and fourth groups received, respectively, growth hormone, ACTH, and growth hormone+ACTH. One hypophysectomized and one non-surgical group maintained at sea-level and one non-surgical group exposed to hypoxia served as controls. Exposure of hypophysectomized rats to hypoxia produced a proportional loss of body and heart weight with an equal decrease in both LDH subunits, H (heart) and M (muscle). Growth hormone and/or ACTH did not reverse cardiac atrophy. ACTH given alone or with growth hormone enhanced M-subunit synthesis (2- to 4-fold) and corrected the H/M ratio to the level of the non-surgical controls exposed to hypoxia, but at the expense of a lower total level of LDH. The adaptative changes in LDH isoenzymes induced by hypoxia could be abolished with hypophysectomy, and partly restored by giving growth hormone and ACTH, but this restoration was not coupled with cardiac growth.
研究了垂体在心脏生长以及在三组垂体切除大鼠为期3周的低压缺氧（9.5%氧气）过程中心肌乳酸脱氢酶（LDH）同工酶适应方面的作用：一组未接受激素，第二、第三和第四组分别接受生长激素、促肾上腺皮质激素（ACTH）以及生长激素+ACTH。一组垂体切除且维持在海平面的大鼠和一组未手术的大鼠以及一组暴露于缺氧环境的未手术大鼠作为对照。垂体切除大鼠暴露于缺氧环境会导致体重和心脏重量成比例下降，同时LDH的两个亚基，即H（心脏型）和M（肌肉型）等量减少。生长激素和/或促肾上腺皮质激素并未逆转心脏萎缩。单独给予促肾上腺皮质激素或与生长激素一起给予时，会增强M亚基的合成（2至4倍），并将H/M比值校正至暴露于缺氧环境的未手术对照组的水平，但代价是LDH的总水平降低。缺氧诱导的LDH同工酶的适应性变化可通过垂体切除消除，并通过给予生长激素和促肾上腺皮质激素部分恢复，但这种恢复与心脏生长无关。
