RESUMEN
The localization of adrenocorticotropin(ACTH),secretogranin Ⅱ in rat pituitary gland Was studied by using specific antisera in conjunction with double immunofluorescence staining techniques.Stainings with secretogranin Ⅱ serum showed intense cytoplasmic reaction in the anterior lobe of the pituitary gland.Double immunofluorescence staining was used to identify the cells that expressed secretogranin Ⅱ and ACTH.Confocal laser scanning microscopy revealed that ACTH existed simultaneouslywith secretogranin Ⅱ in quite a number of cells.The results indicate that secretogranin Ⅱ is expressed in corticotrophs of rat pituitary gland,its physiological role may be associated with the regulation of optimal pH in the secretory vesicles for the cleavage of ACTH from its precursor.