Human pituitary gonadotropic adenoma; histological, immunocytochemical, and ultrastructural and hormonal studies in eight cases

Abstract

Among 230 surgically removed pituitary adenomas, eight tumours showing immunostaining gonadotropic cells and elevated intratumours gonadotropin concentrations have been detected (frequency: 3.5 per cent.). By light microscopy the tumours were composed of agranular cells and generally PAS negative cytoplasm. The immunofluorescence technique revealed the presence of immunoreactive FSH (beta-subunit) alone in two cases, of both FSH and LH in six cases with immunoreactive beta endorphin in two of them. By electron microscopy, the cells contained an often dilated moderately or well developed rough endoplasmic reticulum, secretory granules measuring 150 nm to 200 nm which varied in electron density, and numerous microtubules. Basal plasma FSH and LH levels were simultaneously elevated in two cases; FSH levels alone were elevated in two cases; in three cases, both FSH and LH plasma values were normal. FSH and LH intratumour concentrations were simultaneously elevated in five cases; FSH alone was elevated in two cases. In all cases, the concentrations of the other hormones were negligible, except in two cases where beta endorphin concentration was elevated. The comparison of the immunocytochemical findings, the hormonal plasma levels and intratumour concentrations showed a good relationship between the immunoreactivity of the tumour and the intratumour RIA. The gonadotropic adenoma is uncommon but not rare. Its diagnosis is possible if immunocytochemical techniques are applied.

Glycoprotein hormone genes are expressed in clinically nonfunctioning pituitary adenomas.

“…1 C, "GH" Although several adenomas contained a-subunit mRNA without immunostaining for free a-subunit, in each case there was immunostaining for the intact glycoprotein hormones in which the a-subunit is combined with 1-subunit. The prevalence of glycoprotein hormone immunostaining reported previously for nonfunctioning adenomas varies widely (27)(28)(29)(30)(31), likely reflecting differences in fixation techniques or the sensitivities of different antisera. However, characterization of adenomas by analyses of gene expression and by immunohistochemistry in this study provides convincing evidence for the common occurrence of the glycoprotein hormone cell phenotype using independent techniques.…”

Galanin regulates prolactin release and lactotroph proliferation

“…However, in autopsy series of elderly females the prevalence is 1,000-fold greater, emphasizing that most prolactinomas are clinically silent and common in the elderly population (6). Prolactinomas are also a common cause of death in female aged rats of a number of strains (7)(8)(9). Treatment of prolactinomas with dopamine agonists reduces pituitary prolactin expression and reverses lactotroph hyperplasia, emphasizing the link between prolactin expression and cellular proliferation.…”

Gene expression in pituitary adenomas: New insights

“…The characteristic paranuclear dot pattern of immunostaining for PRL-detecting hormone in the Golgi of the sparsely granulated PRL cell adenoma is well recognised . All classical pituitary hormones have been identified in tumours, although gonadotroph adenomas were first recognised only in the mid to late 1970s (Snyder, 1985;Trouillas et al, 1981). Functioning thyrotroph adenomas are rare Saeger and Ludecke, 1982).…”