Mehendale H M
Pediatr Res. 1980 Apr;14(4 Pt 1):282-5. doi: 10.1203/00006450-198004000-00004.
Pulmonary aldrin epoxidase activity was determined in 2-, 4-, 6-, 8-, 12-, and 16-week-old male rabbits using isolated perfused lung preparations and in vitro incubation techniques. In the perfusion experiments, it was determined that aldrin epoxidase activity increased with age up to 12 weeks of age. Although there was an increase in the weight of lungs with age, this did not appear to be related to the increase in aldrin epoxidation. In vitro experiments carried out using the same substrate to tissue ratio failed to exhibit an age-related increase in the aldrin epoxidase activity. Extrapolated values for aldrin epoxidation from in vitro experiments yielded much higher values than realized from perfusion experiments. Accessibility of the substrate to the enzymatic sites, saturation of the accessible enzyme system, and limiting availability of the cofactor necessary for the oxidative reaction remain as the possible mechanisms for the discrepancy between perfusion and in vitro incubation studies.
采用离体灌注肺制备方法和体外孵育技术，测定了2周龄、4周龄、6周龄、8周龄、12周龄和16周龄雄性家兔的肺艾氏剂环氧化酶活性。在灌注实验中，确定艾氏剂环氧化酶活性在12周龄前随年龄增长而增加。虽然肺重量随年龄增加，但这似乎与艾氏剂环氧化作用的增加无关。使用相同底物与组织比例进行的体外实验未显示艾氏剂环氧化酶活性随年龄增长而增加。体外实验中艾氏剂环氧化的外推值远高于灌注实验中的实际值。底物与酶位点的可及性、可及酶系统的饱和以及氧化反应所需辅助因子的有限可用性，仍是灌注研究和体外孵育研究结果存在差异的可能原因。
