ISSN:
1432-0878
Keywords:
Endothelin receptor Immunohistochemistry Thyrotrophs Rat (AR ++/+sl; Wistar)
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Medicine
Notes:
Abstract. Endothelins modulate hormonal secretion in the pituitary gland. Intense signaling of endothelin A receptors (ETAR) has been detected by in situ hybridization, binding assay and receptor autoradiography. We used light- and electron-microscopic immunohistochemistry of ETAR with polyclonal antibody against a synthetic peptide corresponding to the carboxyl terminus (403–427) of human ETAR. Immunoreactivity was observed in 6–8% of anterior pituitary cells, which were rather large polygonal or stellate cells. These cells were often clustered. Double-staining immunofluorescence showed that the ETAR-positive cells immunoreacted with antibody against the β-subunit of thyroid-stimulating hormone (TSH), but not adrenocorticotropic hormone (ACTH) or lutenizing hormone β (LHβ). Pre- and postembedding electron-microscopic immunohistochemistry showed that ETAR-positive cells had vacuolated or parallel-lined rough endoplasmic reticulum (rER) and numerous round granules in their periphery and the elongated processes. By pre-embedding immunohistochemistry, diaminobenzidine tetrahydrochloride (DAB) products were shown to be mostly located around the granules and occasionally underneath the plasma membrane. By postembedding immunohistochemistry, granules in the ETAR-positive cells were 90–150 nm in diameter, and colloidal gold particles due to ETAR were associated with about 10% of these granules. These results indicate that ETA receptors are associated mostly with the secretory granules of TSH cells.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/s004419900169
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