IMMUNODETECTION OF INSULIN-LIKE-GROWTH-FACTOR I (IGF-I) IN NORMAL ANDPATHOLOGICAL ADRENOCORTICAL TISSUE

IGF-I is one of the peptides that participates in normal adrenocortica l cell growth and, possibly, in the genesis and/or maintenance of tumo rs and hyperplasias of the adrenal cortex. An immunohistochemical tech nique was used for the analysis of IGF-I expression in eight control a nd four hyperplastic adrenals, 11 adrenal cortical adenomas, and 18 ad renal cortical carcinomas. A large number of IGF-I positive cells with granular cytoplasmic (GC) staining pattern was found in the reticular is layer of control adrenal tissues. Fifty percent of the hyperplasias had the GC pattern and the other 50% a mixed pattern; in 64% of the t umors, the adenomas showed a LM (linear membrane) pattern, while adeno carcinomas usually showed a GC pattern (94%). Approximately 75% of the hyperplasias had between 10 and 50% of IGF-I positive cells, while ad enomas and carcinomas had over 50% of IGF-I positive cells in 64% and 83% of the samples, respectively. The size of the tumors with 50% posi tive cells, compared with those with less than 50%, was, on average, g reater, but no statistical differences between cell positivity and cor responding clinical syndrome were observed. Thus, detection of IGF-I i n control and pathological adrenal tissue suggests participation of th is growth factor in cell function and/or growth and proliferation.