Autoradiographical investigations on the affinity of acetyl-(103Ru)-ruthenocene for the adrenal glands of mice.

Whole-body autoradiography was used to investigate the distribution of acetyl-103-ruthenium-(103Ru)-ruthenocene in female mice 2 and 24 h after intravenous application. Two hours after the application of acetyl-(103Ru)-ruthenocene, the nasal mucosa, colon, lung, liver, spleen and especially the adrenal glands were labelled. After 24 h, apart from the absence of labelling of the colon, the labelling pattern did not differ from that obtained 2 h after application. Again, the adrenal glands were particularly strongly labelled. Microautoradiography was performed to investigate the distribution of acetyl-(103Ru)-ruthenocene within the adrenal glands. It was shown that acetyl-(103Ru)-ruthenocene labelling was restricted to the zona reticularis and the inner zona fasciculata of the adrenal cortex. After the stimulation of glucocorticoid synthesis in the adrenal cortex by adrenocorticotropic hormone (ACTH) pretreatment, the labelled area in the zona fasciculata was clearly enlarged. It is concluded that acetyl-(103Ru)-ruthenocene has an affinity for those regions of the adrenal glands where androgen and glucocorticoid synthesis occur.