TISSUE-SPECIFIC HIGH-LEVEL EXPRESSION OF HUMAN ENDOGENOUS RETROVIRUS-R IN THE HUMAN ADRENAL-CORTEX

In an attempt to clarify the biological nature of a human endogenous r etrovirus (HERV), HERV-R, which is a single-copy type of HERVs and is conserved as a full-length viral sequence, the expression of HERV-R mR NA in normal autopsied systemic organs was examined by Northern blot a nalysis. The expression showed different levels among individuals, wit h the adrenal glands expressing the highest level of HERV-R among all organs tested, except for the placenta. In various adrenal tumors, HER V-R was expressed at high levels in all cortical adenomas but less so in pheochromocytomas. In situ hybridization revealed the expression of HERV-R to be localized in all layers of the adrenal cortex, but not i n the medulla. This high-level expression of HERV-R in the adrenal cor tex may possibly relate to differentiation and/or steroid production b y adrenocortical cells.