The effect of bromocriptine on the intermediate lobe of the rat pituitary: an electron-microscopic, morphometric study

1989 ◽  
Vol 255 (2) ◽  
Author(s):  
Nils B�ck
1993 ◽  
Vol 272 (1) ◽  
pp. 79-88 ◽  
Author(s):  
Paul M. Gross ◽  
Madan G. Joneja ◽  
Judy J. Pang ◽  
Trevor M. Polischuk ◽  
Steven W. Shaver ◽  
...  

Author(s):  
D. J. McComb ◽  
N. Ryan ◽  
E. Horvath ◽  
K. Kovacs ◽  
E. Nagy ◽  
...  

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).


1974 ◽  
Vol 22 (8) ◽  
pp. 782-801 ◽  
Author(s):  
JOHN P. PETRALI ◽  
DENNIS M. HINTON ◽  
GWEN C. MORIARTY ◽  
LUDWIG A. STERNBERGER

Araldite sections of rat pituitary intermediate lobe were used with anti-17-39 adrenocorticotropin in the unlabeled antibody enzyme method to compare electron microscopic immunocytochemical staining by peroxidase-antiperoxidase complex (PAP) with antiserum or purified antibody to peroxidase followed by peroxidase (PO). Quantitation of normalized optical densities of secretory granules offered high significance comparison (P < 0.0001) of experimental with control values and of experimental values with each other. Use of purified antibody (prepared by a new density gradient method) yielded four times higher sensitivity than antiserum to PO, while a 6.5-fold increase would have been expected from the degree of contamination of anti-PO in the serum by nonanti-PO immunoglobulin. Use of PAP was four to five times more sensitive than purified anti-PO and 20 times more sensitive than antiserum to PO. The increased sensitivity of PAP is explained by the high over-all binding affinity of PO for anti-PO in the cyclic PAP molecule, thus preventing the losses of PO that occur during washing when anti-PO and PO have been applied in sequence. Identification of the characteristic, cyclic PAP molecules affords confirmation of specific staining at high resolution. In the sequential application of anti-PO and PO, no PAP molecules are formed, thus making distinction of specific from nonspecific deposition of enzyme reaction products ambiguous. With the use of anti-17-39 ACTH and the intermediate lobe, the unlabeled antibody enzyme method was 16,000-100,000 times more sensitive than radioimmunoassay.


Author(s):  
J. W. KEBABIAN ◽  
M. BEAULIEU ◽  
T. E. COTE ◽  
R. L. ESKAY ◽  
E. A. FREY ◽  
...  

1985 ◽  
Vol 101 (1) ◽  
pp. 305-311 ◽  
Author(s):  
P Kristensen ◽  
L S Nielsen ◽  
J Grøndahl-Hansen ◽  
P B Andresen ◽  
L I Larsson ◽  
...  

We immunocytochemically stained rat pituitary glands using antibodies against plasminogen activators of the tissue type (t-PA) and the urokinase type (u-PA). A large population of endocrine cells in the anterior lobe of the gland displayed intense cytoplasmic immunoreactivity with anti-t-PA. In some areas of the intermediate lobe we found a weak staining, and we observed weakly staining granular structures in the posterior lobe. Controls included absorption of the antibodies with highly purified t-PA. In addition, SDS PAGE followed by immunoblotting of pituitary gland extracts revealed only one band with an electrophoretic mobility similar to that of t-PA when stained with anti-t-PA IgG. No u-PA immunoreactivity was detected in the rat pituitary gland. Sequential staining experiments using antibodies against growth hormone and t-PA demonstrated that the t-PA-immunoreactive cells constitute a large subpopulation of the growth hormone-containing cells. These findings represent the first direct evidence for the presence of t-PA in cell types other than endothelial cells in the intact normal organism. In this article we discuss the implications of the results for a possible role of t-PA in the posttranslational processing of prohormones.


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