| Abstract: | It Has been well established that the estrogens, estrone and estradiol, enter the brain from the circulatory system. These compounds are concentrated and retained in the hypothalamus and preoptic regions, particularly in the nuclei of the cells in these regions (Mc Ewen , ZIGMOKD, AZMITIA and Weiss , 1970; Zigmond and Mcewen , 1970). In a previous communication from this laboratory we indicated that a small portion of blood bound dehydroepiandrosterone sulfate enters the brain intact and then is converted to free dehydroepiandrosterone and to androstenediol sulfate (Kishimoto and Hoshi , 1972). Estrone sulfate is the most abundant estrogen in plasma at a concentration of 0.349 pg/ml of plasma, a level which is as much as 10-fold higher than that of free estrone and estradiol in both male and female plasma (Loriaux , Ruder and Lipsett , 1971). Therefore, we deemed it important to establish whether estrone sulfate also enters the brain and if it acts as the source of other brain estrogens. In this communication, we wish to report the results obtained by intracardiac and intracerebral injection of 3H] estrone 35S] sulfate into the developing rat. |
