Immunohistochemical demonstration of alpha1-antichymotrypsin and alpha1 -antitrypsin in the normal pituitary gland and its tumors

Investigation of the Presence of Apotipoprotein E, G lycosaminoglycans, Basement Membrane Proteins, and Protease inhibitors in Senile interstitial Amyloid of the Pituitary

The aim of our study was to test whether local- or organ-limited interstitial amyloid of the pituitary is associated with the presence of glycosaminoglycans, basement membrane proteins, protease inhibitors, and apolipoprotein E (apo E), as previously observed in other amyloid syndromes. Serial sections from amyloidotic and nonamyloidotic autopsy pituitaries of patients age 85 yr and over were stained with Congo red, Alcian blue, and, applying immunohistochemistry, with antibodies directed against fibronectin, collagen IV, laminin, apo E, a(1)-antitrypsin and a(1)-antichymotrypsin. Interstitial amyloid was deposited in the immediate vicinity of capillaries and around the acini of the anterior lobe. Glycosaminoglycans were found in capillaries and around the acini of both nonamyloidotic and amyloidotic glands and they were also related spatially to amyloid deposits. Immunostaining of nonamyloidotic and amyloidotic glands demonstrated the presence of fibronectin, collagen IV, and laminin, which was related to basement membranes (fibronectin, collagen IV, and laminin), interstitium, and serum (fibronectin only). In amyloidotic glands, each basement membrane protein presented with an additional spatial relationship to amyloid deposits. Apo E was found in amyloidotic cases only within the amyloid deposits. The results are consistent with the presence of glycosaminoglycans, basement membrane proteins, and apo E in local interstitial amyloid deposits of the pituitary, as previously described in other amyloid syndromes, such as inflammatory related AA-amyloidosis or AB-amyloidosis related to Alzheimer's disease.

Folliculostellate cells in pituitary adenomas: Studies of hormonal profile and tumor vascularity

The hormonal immunoreactivity and vascularity of pituitary adenomas containing folliculostellate (FS) cells have been compared with those of tumors in which such cells were not identified. FS cells were present in variable numbers in 36 of 92 tumors. Adenomas immunoreactive for growth hormone (GH), adrenocorticotropic hormone (ACTH), or prolactin (PRL) contained FS cells in 40-50% of cases. Those immunoreactive for glycoprotein hormones and alphasubunit contained FS cells in 67-85% of cases, a statistically significant correlation. When alpha-subunit was also present in GH-, GH/PRL-, and ACTH-immunoreactive tumors, a higher proportion contained FS cells (57-91%). These data suggest a correlation between the presence of FS cells and glycoprotein immunoreactivity in pituitary adenomas. Vascular channels identified by the binding of the lectinUlex europaeus were quantified in the two types of tumors. Those containing FS cells were not more vascular than those without FS cells, which suggests that FS cells do not play a significant role in the regulation of intratumoraf vascularization in human pituitary adenomas.

Non-isotopic in situ hybridization with digoxigenin and alkaline phosphatase labelled oligodeoxynucleotide probes. Applications in pituitary gland

We report the application of digoxigenin labelled oligonucleotide probes for the detection of hormonal messenger RNAs (mRNAs) in human pituitary adenomas. Positive signal for the appropriate mRNA was detected in tumours associated with Cushing's disease, acromegaly and hyperprolactinaemia, where immunoreactivity for adrenocorticotrophin (ACTH) growth hormone and prolactin had also been confirmed. In addition, we report the detection of proopiomelanocortin (POMC) mRNA in the rat pituitary gland using an oligodeoxynucleotide probe directly linked to alkaline phosphatase.