Analysis of mammosomatotropic cells in normal and neoplastic human pituitaries

The reverse hemolytic plaque assay (RHPA) was used to analyze hormone secretion in normal and neoplastic human pituitary cells. Immunocytochemical (ICC) staining for PRL and GH with the peroxidase method and ultrastructural ICC with colloidal gold labeling were used along with the RHPA to analyze for mammosomatotropic (MS) cells in these dissociated and cultured pituitary cells. MS cells were identified in both normal and neoplastic pituitary tissues. Quantitation of plaque areas, showed that PRL cells from normal pituitaries had significantly larger plaque areas than PRL cells from PRL-producing adenomas or from mixed PRL-GH producing adenomas.