Quarterly Journal of Microscopical Science, Vol s3-105, 467-473, Copyright © 1964 by Company of Biologists

Studies of differential Staining with Acid dyes in the Human Adenohypophysis

¹ Anatomy Department, University of Manchester

With Mallory techniques the differential staining characteristics in the human adenohypophysis are mainly dependent upon the treatment with phosphotungstic acid. Though this does not remove dye which is already bound to the acidophils it prevents the subsequent access there of anilin blue or acid fuschin, but not of orange G. The molybdenum blue reaction, used after treatment of sections with phosphomolybdic acid, shows that hexavalent molybdenum is strongly bound to the basiphils but more weakly to the acidophils; it can be inferred that phosphotungstic acid reacts with the tissues in a similar manner. Deamination, acetylation, and benzoylation produce a marked reduction in dye-binding, though the granules of the basiphils are resistant to the benzoylation. Methylation results in a marked increase in the staining of all elements. The differential effect of the phosphotungstic acid is abolished, so that the dyes are able to gain admission to the acidophils after the polyacid treatment.

The differential staining is most probably dependent upon the differing permeabilities of the tissue proteins to molecules of differing sizes, the acid fuchsin, anilin blue, and phosphotungstic acid competing with each other for basic groups. On the other hand, it is possible that phosphotungstic acid has a different type of reaction with the acidophils, involving chelate linkages to carboxyl and other groups of the tissue proteins.