THE LOCALIZATION OF GLYCOPROTEIN HORMONES IN THE ANTERIOR PITUITARY GLANDS OF RATSINVESTIGATED BY DIFFERENTIAL PROTEIN SOLUBILITIES, HISTOLOGICAL STAINS AND BIO-ASSAYS12

Abstract

ONE of the physical properties of proteins, that of differential solubility, is not usually taken advantage of when the routine methods of fixation are used prior to histological or histochemical staining procedures. However, it should be possible to expose a tissue containing a mixture of proteins to a reagent in which some of the proteins were denatured and rendered insoluble, while other soluble proteins were not denatured and were extracted. Because of the reversibility of denaturation with some reagents and because solvents are employed in the preparation of tissue sections, it is possible to use a second fixative containing a reagent that will combine with the proteins which were not extracted, precipitating them irreversibly so that they can be subsequently stained. In this manner, it should be possible to extract certain proteins from a mixture of proteins in a tissue, following which comparison of stained sections of the extracted tissue with sections of the same tissue in which all the proteins had been precipitated, would reveal the sites of the extracted proteins. After this procedure, which reduced the number of proteins, it should be possible to characterize the remainder more exactly by various staining reactions.