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Cryoultramicrotomy versus plastic embedding: comparative immunocytochemistry of rat anterior pituitary cells
Author(s) -
Hemming F. J.,
Mesguich P.,
Morel G.,
Dubois P. M.
Publication year - 1983
Publication title -
journal of microscopy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.569
H-Index - 111
eISSN - 1365-2818
pISSN - 0022-2720
DOI - 10.1111/j.1365-2818.1983.tb04227.x
Subject(s) - antigenicity , glutaraldehyde , endoplasmic reticulum , immunocytochemistry , ultrastructure , frozen section procedure , anterior pituitary , embedding , fixation (population genetics) , chemistry , phosphate buffered saline , antibody , osmium , immunohistochemistry , biology , microbiology and biotechnology , hormone , biochemistry , anatomy , endocrinology , pathology , chromatography , immunology , medicine , computer science , catalysis , artificial intelligence , gene , ruthenium
SUMMARY The anterior pituitary of the rat is used as a model for the study of the effects of freezing or plastic embedding on the maintenance of antigenicity. Rat anterior pituitaries are fixed in 2.5% glutaraldehyde in 0.1 m phosphate buffer pH 7.4. Some of the blocks are post‐fixed before being divided into two lots. One batch is frozen, while the other is dehydrated and embedded. The indirect antibody enzyme method is applied to ultrathin sections obtained by cryoultramicrotomy after freezing or by sectioning after embedding. All six pituitary hormones are detected by both methods. Comparison shows that the morphological characteristics are identical for both techniques, though ultrastructural preservation is better after embedding. Immunoreactivity is found in secretory granules and sometimes in the endoplasmic reticulum. Osmium postfixation may reduce or even abolish antigenicity in plastic‐embedded tissue. After cryoultramicrotomy, however, even after osmium fixation, antibody may be used 1000 times more diluted than after plastic embedding. Embedding preserves ultrastructure and limited antigenicity while the use of cryoultramicrotomy is a far more sensitive technique.