M ammary Excretion of 2O@Methy1cho1anthrene*
نویسنده
چکیده
Recently, evidence was reported for the belief that a carcinogenic agent, †̃20-methyleholanthrene, could be secreted into the milk of a lactating ani mal and thereby gain entrance into the bodies of the offspring to cause an abnormally high mci dence of neoplasms (1). Further positive evidence for this mode of excretion of methyleholanthrene has now been obtained by means of ultraviolet ab sorption spectroscopy, a method which has been used widely to follow the distribution of this and other carcinogens in animal tissues (†̃2). In the detection of methylcholanthrene in tis sues of rats, advantage was taken of its high ab sorption peaks at †̃284 and †̃295 [email protected] solution of 1 @sg. per milliliter in petroleum ether has an opti cal density (log 100/per cent transmission) of .†̃250 at †̃284 and .31'2 at †̃295 m@ (measurements made with a Beekmann model DU spectrometer). The sensitivity of this method is limited by the fact that the unsaponifiable matter of rat tissues dis plays rather high general absorption in the ultra violet, which increases with decreasing wave length (Fig. 1). As shown in Figure 1, however, the addition of methyleholanthrene in a concentration of 0.1 sg. per milliliter can be readily detected by inflections in the absorption curve of such an ex tract. Since the absorption of solutions of the Un saponifiable matter of a whole rat is such that it can be conveniently measured in a dilution of about 100 ml., the presence of methylcholanthrene in the bodies of rats in the amount of 10 jig. should be detectable by inflections at †̃284 and †̃295 m@z; and amounts of approximately 50 @g. should ap pear as discernible peaks on the absorption curve. In the present work, inflections at †̃284 and †̃295 mjs were taken asqualitative evidence for the presence of methyleholanthrene, with the recognition, of course, of the possibility that part or all of the ab
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