Histochemical Differentiation of Anterior Pituitary Cell Types by Contrasting Azocoupling and Mucoprotein Stains

Abstract
Azo compounds couple with aromatic amino-acid nuclei in the cytoplasmic proteins of human anterior pituitary acidophile and basophile cells. In acidophile cells the reaction appears to be due primarily to tyrosine, but also in part to histidine. Procedures are given for the use of naphthanil diazo blue B (tetrazotized di-ortho-anisidine), with or without a second coupling agent (H acid; 8-amino-1-naphthol-3, 6-disulfonic acid), to demonstrate acidophile cells, in contrast to mucoprotein stains (periodic acid oxidation followed by leukofuchsin or leukothionin) for the cytoplasm of basophile cells. Evans blue can also be used to give a contrasting color to basophile cells.