Lynn M D, Gross M D, Shapiro B
Nucl Med Commun. 1986 Aug;7(8):625-30. doi: 10.1097/00006231-198608000-00009.
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.
