CORRELATION OF MAST-CELLS WITH SPINDLE-CELL HYPERPLASIA IN THE ADRENAL-CORTEX OF IQI JIC MICE/

IQI/Jic mice showed a high incidence of subcapsular spindle cell hyper plasia (SCH) in the adrenal cortex accompanied by prominent mast cell infiltration. SCH-positive animals appeared as early as at 3 months of age, with an incidence of 18% in males and 20% in females. Except for one mouse, all females older than 6 months had the lesion. In males, the incidence increased gradually until 9 months, and was then stable at 75-88% thereafter. The severity of SCH increased with age in both s exes, and the lesions were more prominent in females. Mast cells infil trated mainly at the sites of spindle cell hyperplasia, and their dens ity was associated with the severity of the lesion. A quantitative mor phometric study confirmed a significant correlation between the severi ty of SCH and the density of mast cells. A histochemical study demonst rated that these mast cells were of the connective tissue-type. These observations indicate that IQI/Jic mice may be a useful strain to eluc idate the pathogenesis of SCH in the adrenal cortex in association wit h mast cell function.