Mills T M, Lin T J, Braselton W E, Ellegood J O, Mahesh V B
Am J Obstet Gynecol. 1976 Dec 15;126(8):987-92.
Previous studies from this laboratory reported that 3H-labeled metabolites with half-lives of more than 24 hours may remain in the plasmaa of women receiving an intravenous injection of 3H norethindrone or 3H mestranol. To confirm the presence of these metabolites, blood samples were collected for five days after injection of 3H norethindrone or 3H mestranol; 3H representing metabolites of norethindrone disappeared with half-life values of 42 to 84 hours (mean 67 hours), while 3H representing metabolites of mestranol declined with an average half-life of 45 hours (range 37 to 65 hours). When the 3H-labeled drugs were administered orally, metabolites of similar half-life were formed. Because these compounds exist for several days after a single administration and since oral contraceptive drugs are normally taken daily, the possiblity of the accumulation of 3H in the plasm of women receiving several consecutive doses of 3H norethindrone was investigated. The results of this study show a stepwise accumulation of the 3H metabolites when 3H norethindrone was administered in six daily oral doses. However, the 3H levels declined from the peak on the sixth and last day of the treatment at a rate equivalent to those previously measured after intravenous or oral administration.
该实验室之前的研究报告称，半衰期超过24小时的3H标记代谢物可能会残留在接受静脉注射3H炔诺酮或3H炔雌醇甲醚的女性血浆中。为了证实这些代谢物的存在，在注射3H炔诺酮或3H炔雌醇甲醚后采集血样，为期五天；代表炔诺酮代谢物的3H以42至84小时的半衰期值消失（平均67小时），而代表炔雌醇甲醚代谢物的3H以平均45小时的半衰期下降（范围为37至65小时）。当口服3H标记药物时，会形成半衰期相似的代谢物。由于这些化合物在单次给药后会存在数天，且口服避孕药通常每天服用，因此研究了连续接受数剂3H炔诺酮的女性血浆中3H积累的可能性。这项研究的结果表明，当3H炔诺酮以每日六次口服剂量给药时，3H代谢物会逐步积累。然而，3H水平在治疗的第六天及最后一天从峰值下降，下降速率与之前静脉注射或口服给药后测得的速率相当。
