Yadav R N, Singh S N
Biochim Biophys Acta. 1980 Dec 15;633(3):323-30. doi: 10.1016/0304-4165(80)90192-0.
The activity and hormonal regulation of NAD- and NADP-linked isocitrate dehydrogenase (EC 1.1.1.41 and 1.1.1.42, respectively) in the brain and liver of rats of various ages were investigated. The activity of NAD-linked isocitrate dehydrogenase of the brain was greater than cytoplasmic or mitochondrial NADP-linked isocitrate dehydrogenase. In contrast, the cytoplasmic NADP-isocitrate dehydrogenase of the liver predominates over both NAD- and mitochondrial NADP-isocitrate dehydrogenases at the three ages studied. The activity of NAD-isocitrate dehydrogenase increased in the brain (139%) and liver (17%) of rats up to 33 weeks of age and decreased (57 and 39%, respectively) in old rats (85-week-old). The activity of cytoplasmic NADP-isocitrate dehydrogenase was maximum in immature (6-week-old) rat brain and decreased as the age of the rats increased; whereas, in liver, the activity of this enzyme was found o be maximum in adult rats (33-week-old). Brain mitochondrial NADP-isocitrate dehydrogenase activity increased (64%) in adult rats, but in liver it decreased (45 and 33% in 33- and 85-week-old rats, respectively). In both tissues, adrenalectomy and hydrocortisone treatment showed differential age-dependent response. Hydrocortisone-mediated induction of the level of enzymes was inhibited by actinomycin D.
研究了不同年龄大鼠脑和肝脏中NAD - 及NADP - 连接的异柠檬酸脱氢酶（分别为EC 1.1.1.41和1.1.1.42）的活性及激素调节。脑NAD - 连接的异柠檬酸脱氢酶的活性高于细胞质或线粒体NADP - 连接的异柠檬酸脱氢酶。相反，在所研究的三个年龄阶段，肝脏的细胞质NADP - 异柠檬酸脱氢酶的活性均高于NAD - 及线粒体NADP - 异柠檬酸脱氢酶。在33周龄前大鼠的脑（增加139%）和肝脏（增加17%）中，NAD - 异柠檬酸脱氢酶的活性升高，而在老年大鼠（85周龄）中则降低（分别降低57%和39%）。细胞质NADP - 异柠檬酸脱氢酶的活性在未成熟（6周龄）大鼠脑中最高，并随大鼠年龄增加而降低；而在肝脏中，该酶的活性在成年大鼠（33周龄）中最高。成年大鼠脑线粒体NADP - 异柠檬酸脱氢酶的活性增加（64%），但在肝脏中则降低（33周龄和85周龄大鼠分别降低45%和33%）。在这两种组织中，肾上腺切除术和氢化可的松处理显示出不同的年龄依赖性反应。放线菌素D抑制了氢化可的松介导的酶水平诱导。
