AD4BP IN THE HUMAN ADRENAL-CORTEX AND ITS DISORDERS

Ad4BP, a zinc finger DNA-binding protein, is a transcription factor th at regulates the expression of the steroidogenic P450 genes. We perfor med immunoblotting and immunohistochemistry of Ad4BP in 34 human adren al cortex specimens, which included adrenocortical adenomas and carcin omas. Immunoblotting revealed a single band of 53K, corresponding to t he mol wt of Ad4BP. The immunohistochemical studies demonstrated that Ad4BP immunoreactivity was present exclusively in the nuclei of nearly all of the adrenocortical parenchymal cells in both the normal and th e pathological human adrenal specimens. Ad4BP was immunostained with e qual intensity and frequency among the different cell types, Ad4BP imm unoreactivity was also observed in areas of marked degenerative change s, such as lipomyelomatous lesions, and in poorly differentiated carci noma cells. These results suggest a close association of Ad4BP express ion with the biological phenotype of adrenocortical parenchymal cells. Ad4BP therefore seems to play important roles in the induction and ma intenance of the transcription of all steroidogenic P450 genes in huma n adrenocortical cells, even after malignant transformation.