Studies upon the Gram Reaction of the Basiphil Cells of the Anterior Pituitary

The basiphil cell granules of the human anterior pituitary react positively with Gram's stain, but no specific differentiation of these granules occurs when the iodine treatment is omitted. The granules of the acidophil cells are Gram-negative. Various workers have suggested a connexion between the Gram reaction of various micro-organisms and the presence of ribonucleoprotein, and the pituitary cells were investigated from this point of view. Pyronin methyl green staining demonstrates what is probably ribonucleoprotein material in the cytoplasm of both chromophobes and chromophils, but not in the granules of either kind of chromophil. As with micro-organisms, the Gram reaction is destroyed by treating the sections with hot oxygenated bile salt, which has a detergent action upon the ribonucleic acids, but, unlike micro-organisms, the reaction remains unaffected by digestion with a buffered solution of crystalline ribonuclease, although this treatment destroys the nucleic acid, as demonstrated by the loss of pyronin basiphilia in the cytoplasm. Bile salt also diminishes the strong positive reaction of the basiphil cell granules to the periodic acid Schiff (P.A.S.) test—a reaction which probably indicates the presence of intragranular mucoprotein. It seems unlikely that the Gram-positive reaction of the basiphil cell granules of the human anterior pituitary is due simply to the presence of ribonucleoprotein. We have employed the term ribonucleic acid, bearing in mind that this is a generic term and not the name of a single molecular species (cf. Davidson, 1950).