长期肾上腺切除且接受或未接受糖皮质激素替代治疗的大鼠心肌收缩蛋白ATP酶的变化

Changes in myocardial contractile protein ATPases in chronically adrenalectomized rats with and without glucocorticoid replacement.

作者信息

Bhaskar M, Stith R D, Brackett D J, Wilson M F, Lerner M R, Reddy Y S

机构信息

Department of Physiology, University of Oklahoma Health Sciences Center, Oklahoma City.

出版信息

Biochem Med Metab Biol. 1989 Oct;42(2):118-24. doi: 10.1016/0885-4505(89)90047-9.

DOI:10.1016/0885-4505(89)90047-9

PMID:2528974

Abstract

Studies were conducted to examine the effects of chronic adrenalectomy (Adx) and adrenalectomy plus glucocorticoid replacement therapy on rat cardiac contractile protein ATPase activities. The Ca2+-dependent Mg-ATPase activity of myofibrils isolated from rat ventricles 3 weeks postadrenalectomy (Adx) was significantly decreased at all pCa2+ concentrations (P less than 0.01), compared to sham-operated (SO) rats. Similarly, Ca2+-, K+-EDTA, and actin-activated myosin ATPase activities of Adx rat hearts were markedly decreased below that of SO rats (P less than 0.01). Dexamethasone administration to Adx rats prevented the decrease of Ca2+- and K+-ATPase activities of myosin, but not of myofibrillar Ca2+-dependent Mg-ATPase or actin-activated myosin Mg-ATPase activities. These studies suggest that glucocorticoid insufficiency induced by adrenalectomy results in altered myocardial contractile protein ATPase activity which may underlie impaired cardiac performance.

摘要

开展了多项研究，以检验慢性肾上腺切除术（Adx）以及肾上腺切除术加糖皮质激素替代疗法对大鼠心脏收缩蛋白ATP酶活性的影响。与假手术（SO）大鼠相比，肾上腺切除术后3周从大鼠心室分离出的肌原纤维的Ca2+依赖性Mg-ATP酶活性在所有pCa2+浓度下均显著降低（P<0.01）。同样，Adx大鼠心脏的Ca2+、K+-EDTA和肌动蛋白激活的肌球蛋白ATP酶活性明显低于SO大鼠（P<0.01）。给Adx大鼠注射地塞米松可防止肌球蛋白的Ca2+和K+-ATP酶活性降低，但不能防止肌原纤维Ca2+依赖性Mg-ATP酶或肌动蛋白激活的肌球蛋白Mg-ATP酶活性降低。这些研究表明，肾上腺切除术引起的糖皮质激素不足导致心肌收缩蛋白ATP酶活性改变，这可能是心脏功能受损的基础。