The fine structural localization of peroxidase activity in goblet cells of the conjunctival epithelium of rats.

Cytochemical investigation of peroxidase was made on the conjunctival goblet cells, using the diaminobenzidine method. Many goblet cells in the conjunctiva demonstrated this reaction. The reaction was present in secretory granules as well as in the perinuclear cisterna, the rough endoplasmic reticulum, several Golgi saccules and adjacent small smooth-surfaced vesicles, and condensing vacuoles. Each secretory granule within a goblet cell showed a different degree of reaction, hence it is concluded that some goblet cells probably produce both mucous substance and peroxidase in one cell. The mode of production of peroxidase in goblet cells is concluded to be similar to that of secretory proteins in pancreatic exocrine cells. The enzyme, together with thiocyanate and endogenous hydrogen peroxide, is thought to serve as an anti-infectious agent in tears.