Effects of fuchsin variants in aldehyde fuchsin staining.

Aldehyde fuchsin stains pancreatic B cell granules, hypophyseal basophils, goblet cell mucins, gastric chief cells, hyaline cartilage, and elastica. Neither the chemical structure of aldehyde fuchsin nor its staining mechanism is known. This study was undertaken to clarify the role of the fuchsin component of aldehyde fuchsin in its staining reaction. The major findings of this investigation include: 1) single N-methylation of the fuchsin molecule abolishes staining of unoxidized pancreatic B cells, although it does not prevent reaction of fuchsin with paraldehyde; 2) aldehyde fuchsin is probably a Schiff base condensation product of pararosaniline and acetaldehyde; 3) a Schiff base structure alone cannot account for aldehyde fuchsin staining of unoxidized pancreatic B cells; 4) a fully potent aldehyde fuchsin is possibly a Tris-Schiff base derivative of pararosaniline.