Enterohepatic circulation and distribution of 131I-6 beta-iodomethyl-19-norcholesterol (NP-59).
The enterohepatic circulation and distribution of 131I-6 beta-iodomethyl-19-norcholesterol (NP-59) was assessed in a rabbit model to examine the relative distribution of NP-59 and its metabolites. Adrenal, bile and serum samples were obtained from seven rabbits at 48 h following NP-59 administration (240 to 570 microCi) and the distribution of 131I radioactivity examined using thin layer chromatography. In serum 71% of the radioactivity circulated as NP-59 and 20% as NP-59 esters. In contrast greater than 90% of the adrenal radioactivity was in the form of NP-59 esters while in bile 70% of the activity was NP-59 with the remainder in the form of bile acids. In another group of animals, adrenal activity was observed 5 days after intragastric administration of NP-59. Thus, we have demonstrated a significant enterohepatic circulation of NP-59 that may have the potential to influence the distribution of and resultant adrenal imaging with NP-59.
D015071:19-Iodocholesterol / Q000031:analogs & derivatives* / Q000378:metabolism; D000302:Adrenal Cortex / Q000000981:diagnostic imaging / Q000378:metabolism; D000818:Animals; D001646:Bile; D002784:Cholesterol / Q000031:analogs & derivatives*; D004764:Enterohepatic Circulation; D004952:Esters; D007457:Iodine Radioisotopes; D008954:Models, Biological; D011817:Rabbits; D011877:Radionuclide Imaging
D004952:Esters; D007457:Iodine Radioisotopes; D015071:19-Iodocholesterol; C035501:6-iodomethylcholesterol; D002784:Cholesterol