ISSN:
1432-2307
Keywords:
Key words Activin A
;
Inhibin A
;
Endocrine tumors
;
Digestive system
;
Immunohistochemistry
Source:
Springer Online Journal Archives 1860-2000
Topics:
Medicine
Notes:
Abstract Activin A and inhibin A, first isolated from the ovary, are dimeric proteins able to modulate pituitary FSH secretion. Inhibin A is a heterodimer composed of one α-subunit and one βA-subunit (α-βA), while activin A is a homodimer of the βA-subunit (βA-βA). Their identification in several tissues has suggested that they have numerous physiological functions, acting as either paracrine or autocrine factors. The aim of this study was to evaluate the expression of activin A and inhibin A in normal endocrine cells and in 70 endocrine tumours from different sites in the gastro-entero-pancreatic system, using specific monoclonal antibodies directed against the α- and βA-subunits of inhibin/activin. Immunoreactivity for the βA-subunit, but not for the α-subunit, was observed in normal G, EC, and GIP cells of the antrum and duodenum, and in pancreatic A cells. βA-subunit expression was observed in G cell and A cell tumours, and in a few insulinomas and ileal EC cell carcinoids. The α-subunit was found in rare cells in 7 of the 70 tumours and was colocalized with the βA-subunit in only 1 tumor. Specific types of endocrine cells from the gut and pancreas appear to produce only activin A, a possible paracrine or autocrine modulator. Activin A is mainly produced by tumours derived from endocrine cells that normally express it.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/s004280050301
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