Pituitary Hyperplasia in a Male Mouse after the Administration of Oestrin

Several observers have noticed enlargement of the pituitary gland in animals subjected to oestrogens. This enlargement, as a rule, is distinctly less than that which follows castration. According to Wolfe and Phelps the changes caused by oestrin in the anterior lobe of the rat's pituitary are (1) a degranulation of the eosinophile and basophile cells, with a diminution of their total numbers, and (2) an increase in size and number of the chromophobe cells. Cramer and Horning found pituitary changes in 11 among 12 mice which had been treated by cutaneous applications of oestrin; in three of them pituitary adenomata, consisting mainly of chromophobe cells, were present. Gardner, Strong and Smith have described a pituitary tumour, consisting chiefly of chromophobe cells, which developed spontaneously in an old breeding doe