Caviezel M, Lutz W K, Minini U, Schlatter C
Arch Toxicol. 1984 Jul;55(2):97-103. doi: 10.1007/BF00346046.
[6,7-3H] Estrone (E) and [6,7-3H]estradiol-17 beta (E2) have been synthesized by reduction of 6-dehydroestrone and 6-dehydroestradiol with tritium gas. Tritiated E and E2 were administered by oral gavage to female rats and to male and female hamsters on a dose level of about 300 micrograms/kg (54 mCi/kg). After 8 h, the liver was excised from the rats; liver and kidneys were taken from the hamsters. DNA was purified either directly from an organ homogenate or via chromatin. The radioactivity in the DNA was expressed in the units of the Covalent Binding Index, CBI = (mumol chemical bound per mol DNA-P)/(mmol chemical administered per kg b.w.). Rat liver DNA isolated via chromatin exhibited the very low values of 0.08 and 0.09 for E and E2, respectively. The respective figures in hamster liver were 0.08 and 0.11 in females and 0.21 and 0.18 in the males. DNA isolated from the kidney revealed a detectable radioactivity only in the female, with values of 0.03 and 0.05 for E and E2, respectively. The values for male hamster kidney were less than 0.01 for both hormones. The minute radioactivity detectable in the DNA samples does not represent covalent binding to DNA, however, as indicated by two sets of control experiments. (A) Analysis by HPLC of the nucleosides prepared by enzyme digest of liver DNA isolated directly or via chromatin did not reveal any consistent peak which could have been attributed to a nucleoside-steroid adduct. (B) All DNA radioactivity could be due to protein contaminations, because the specific activity of chromatin protein was determined to be more than 3,000 times higher than of DNA. The high affinity of the hormone to protein was also demonstrated by in vitro incubations, where it could be shown that the specific activity of DNA and protein was essentially proportional to the concentration of radiolabelled hormone in the organ homogenate, regardless of whether the animal was treated or whether the hormone was added in vitro to the homogenate.(ABSTRACT TRUNCATED AT 250 WORDS)
通过用氚气还原6-脱氢雌酮和6-脱氢雌二醇-17β合成了[6,7-³H]雌酮（E）和[6,7-³H]雌二醇-17β（E2）。将氚标记的E和E2以约300微克/千克（54毫居里/千克）的剂量水平经口灌胃给予雌性大鼠以及雄性和雌性仓鼠。8小时后，从大鼠身上切除肝脏；从仓鼠身上取出肝脏和肾脏。DNA要么直接从器官匀浆中纯化，要么通过染色质纯化。DNA中的放射性以共价结合指数（CBI）为单位表示，CBI =（每摩尔DNA-P结合的微摩尔化学物质）/（每千克体重给予的毫摩尔化学物质）。通过染色质分离的大鼠肝脏DNA中，E和E2的值分别非常低，为0.08和0.09。雌性仓鼠肝脏中的相应数值分别为0.08和0.11，雄性为0.21和0.18。从肾脏分离的DNA仅在雌性中显示出可检测到的放射性，E和E2的值分别为0.03和0.05。两种激素在雄性仓鼠肾脏中的值均小于0.01。然而，如两组对照实验所示，DNA样品中可检测到的微量放射性并不代表与DNA的共价结合。（A）通过高效液相色谱法对直接或通过染色质分离的肝脏DNA经酶消化制备的核苷进行分析，未发现任何可归因于核苷 - 类固醇加合物的一致峰。（B）所有DNA放射性可能归因于蛋白质污染，因为染色质蛋白的比活性被确定比DNA高3000倍以上。激素对蛋白质的高亲和力也通过体外孵育得到证明，结果表明DNA和蛋白质的比活性基本上与器官匀浆中放射性标记激素的浓度成正比，无论动物是否接受处理或激素是否在体外添加到匀浆中。（摘要截断于250字）
