Pituitary adenomas

Investigation of the spontaneous pituitary adenomas in rat have been limited mainly to light microscopic study. Furth et al. (1973) described them as chromophobic, secreting prolactin. Kovacs et al. (1977) in an ul trastructural investigation of adenomas of old female Long-Evans rats, found that they were composed of prolactin cells. Berkvens et al. (1980) using immunocytochemistry at the light microscopic level, demonstrated that some spontaneous tumors of old Wistar rats could contain GH, TSH or ACTH as well as PRL.

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Ultrastructural comparison of prolactin adenomas of pituitary in men and women

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100103796 ◽

1988 ◽

Vol 46 ◽

pp. 346-347

Author(s):

R.C. Caughey ◽

U.P. Kalyan-Raman

Keyword(s):

Endoplasmic Reticulum ◽

Electron Microscope ◽

Phosphate Buffer ◽

Pituitary Adenomas ◽

Osmium Tetroxide ◽

Secretory Granules ◽

Uranyl Acetate ◽

En Bloc ◽

Men And Women ◽

Transmission Electron

Prolactin producing pituitary adenomas are ultrastructurally characterized by secretory granules varying in size (150-300nm), abundance of endoplasmic reticulum, and misplaced exocytosis. They are also subclassified as sparsely or densely granulated according to the amount of granules present. The hormone levels in men and women vary, being higher in men; so also the symptoms vary between both sexes. In order to understand this variation, we studied 21 prolactin producing pituitary adenomas by transmission electron microscope. This was out of a total of 80 pituitary adenomas. There were 6 men and 15 women in this group of 21 prolactinomas.All of the pituitary adenomas were fixed in 2.5% glutaraldehyde, rinsed in Millonig's phosphate buffer, and post fixed with 1% osmium tetroxide. They were then en bloc stained with 0.5% uranyl acetate, rinsed with Walpole's non-phosphate buffer, dehydrated with graded series of ethanols and embedded with Epon 812 epoxy resin.

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Fine Structural Classification of Chromophobe Adenomas of the Human Pituitary Gland

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100115511 ◽

1975 ◽

Vol 33 ◽

pp. 378-379

Author(s):

K. Kovacs ◽

E. Horvath

Keyword(s):

Pituitary Adenomas ◽

Secretory Activity ◽

Microscopic Investigation ◽

Uranyl Acetate ◽

Electron Microscopic Investigation ◽

Electron Microscopic ◽

Human Pituitary ◽

Cytoplasmic Staining ◽

Human Pituitary Gland ◽

Microscopic Features

Chromophobe pituitary adenomas arise from adenohypophysial cells and fail to exhibit cytoplasmic staining with conventional acid or basic dyes by light microscopy. The aim of the present work was to study the electron microscopic features of these tumors, to separate them into distinct entities and to correlate their fine structural appearances with secretory activity.Among 48 surgically removed various pituitary adenomas 30 tumors were found which, based on the tinctorial characteristics of the cytoplasm, corresponded to chromophobe adenomas. For electron microscopic investigation pieces of these tumors were fixed in 2.5 per cent glutaraldehyde in Sorensen's buffer, post fixed in 1 per cent osmium tetroxide in Millonig's buffer, dehydrated in graded ethanol and embedded in Epon 812. Ultrathin sections were stained with uranyl acetate and lead citrate.By electron microscopy it was possible to separate chromophobe adenomas into 3 distinct entities: 1) adenomas consisting of sparsely granulated growth hormone cells (7 cases).

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Ultrastructural Immunocytochemistry of Five Rat Pituitary Adenomas

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s1431927600003147 ◽

1980 ◽

Vol 38 ◽

pp. 724-725

Author(s):

D. J. McComb ◽

N. Ryan ◽

E. Horvath ◽

K. Kovacs ◽

E. Nagy ◽

...

Keyword(s):

Pituitary Adenomas ◽

Pituitary Tumors ◽

Electron Microscopic ◽

Electron Microscopic Immunocytochemistry ◽

Transmission Electron ◽

Rat Pituitary ◽

Radiation Induced ◽

Group 5 ◽

Group 2 ◽

Microscopic Techniques

Conventional light and electron microscopic techniques failed to clarify the cellular composition and derivation of spontaneous and induced, intrasellar and transplanted pituitary adenomas in rats (1). In the present work, electron microscopic immunocytochemistry was applied to evaluate five adenohypo-physial tumors using a technique described by Moriarty and Garner (2). Spontaneously occurring pituitary adenomas (group 1) were harvested from aging female Long-Evans rats. R-Amsterdam rats were treated with 2 x 1.0 mg estrone acetate (HogivaI) s.c. weekly for 6 months. Pituitary adenomas in excess of 30 mg were removed from these animals to make up the tumors of group 2. Groups 3 and 4 consisted of estrogen-induced autonomous transplan¬ted pituitary tumors MtT.WlO and MtT.F4. Group 5 was a radiation-induced transplanted autonomous pituitary tumor MtT.W5. The tumors of groups 3,4 and 5 were allowed to proliferate in host rats 6-8 weeks prior to removal for processing. Tissue was processed for transmission electron microscopy (glutaraldehyde fixation, OsO4 postfixation and epoxy resin embedding), and electron microscopic immunocytochemistry (3% paraformaldehyde fixation and Araldite embedding).

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