Immunocytochemical Demonstration of Tissue-Type Plasminogen Activator in Endocrine Cells of the Rat Pituitary Gland

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...

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Bibliographic Details
Published in:The Journal of cell biology 1985-07, Vol.101 (1), p.305-311
Main Authors: Kristensen, Peter, Nielsen, Lars S., Grøndahl-Hansen, Jan, Andresen, Peter B., Larsson, Lars-Inge, Danø, Keld
Format: Article
Language:English
Subjects:
Animals
Antibodies
Biological and medical sciences
Endocrine cells
Endothelial cells
Female
Fundamental and applied biological sciences. Psychology
Growth Hormone - metabolism
Growth hormones
Hypothalamus. Hypophysis. Epiphysis. Urophysis
Immunoenzyme Techniques
Immunosorbent Techniques
Islets of Langerhans
Laboratory staining techniques
Male
Morphology. Functional localizations
Pituitary gland
Pituitary Gland, Anterior - cytology
Pituitary Gland, Anterior - metabolism
Plasminogen activators
Plasminogen Activators - metabolism
Rats
Stem cells
Vertebrates: endocrinology
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Summary: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.
ISSN:0021-9525
1540-8140
DOI:10.1083/jcb.101.1.305