In situ hybridization study of estrogen receptor messenger ribonucleic acid in human adenohypophysial cells and pituitary adenomas.

Abstract

Estrogen receptor (ER) was demonstrated in nontumorous and adenomatous human pituitaries by autoradiography and biochemical assays. In the present study, we investigated ER mRNA by in situ hybridization applied on paraffin section of 9 nontumorous pituitaries obtained at surgery or autopsy and 109 surgically removed adenomas. In nontumorous pituitaries, in situ hybridization combined with immunocytochemistry revealed hybridization signal in GH-, PRL-, ACTH-, TSH-, and LH/FSH-immunoreactive cells, with the highest intensity in PRL-immunoreactive cells. ER mRNA was also localized in Crooke's cells, corticotrophs extending to posterior lobe, cells lining the pars intermedia cavities, and squamous nests of pars tuberalis. The neurohypophysis, endothelium, and connective tissue expressed no ER gene. ER mRNA was present in all adenoma types, including somatotroph, lactotroph, mixed somatotroph-lactotroph, mammosomatotroph, acidophil stem cell, functioning and silent corticotroph, thyrotroph, gonadotroph, null cell adenomas, and oncocytomas. The strongest signal was seen in some lactotroph and mammosomatotroph adenomas. In 9 lactotroph adenomas exposed to bromocriptine (long-acting repeatable injectable form), the hybridization signal was weak or absent, suggesting that suppression of ER gene plays a role in the inhibition of PRL synthesis and tumor growth.

Effects of long-term treatment with 8-prenylnaringenin and oral estradiol on the GH–IGF-1 axis and lipid metabolism in rats

“…Since it has been demonstrated that ERa is expressed in GH-positive cells in the pituitary (Stefaneanu et al 1994) and as radiolabeled estrogen was found in GH immunoreactive cells (Keefer et al 1976), we first determined the effect of E 2 B and 8-PN on pituitary GH secretion. Both the high dose of 8-PN and the high dose of E 2 B significantly upregulated GH levels.…”

Aspectos clínicos e terapêuticos de prolactinomas em homens

“…Embora os homens tenham níveis de estrogênio mais baixos que as mulheres, maior expressão de receptor estrogênico tem sido demonstrada em prolactinomas de homens que nos de mulheres. Este pode ser um dos fatores responsáveis pela maior agressividade da doença no sexo masculino, independente da precocidade ou não do diagnóstico 30,31 .…”

Current perspectives on the pathogenesis of clinically non-functioning pituitary tumours

“…We have documented reduced expression of isoforms of thyroid hormone receptors and retinoid X receptors in NFTs (Gittoes et al 1997a,b) compared with the findings in normal pituitaries. Absent, or reduced, expression of oestrogen receptor ( ) protein has also been demonstrated in NFTs (Nakao et al 1989, Friend et al 1994, Stefaneanu et al 1994, Zafar et al 1995, Gittoes et al 1997a. The latter observation is of particular relevance, as NFTs are believed to be derived from cells of the gonadotroph lineage and thus would be expected to express oestrogen receptor (Friend et al 1994, Zafar et al 1995.…”