Ultrastructural observations on folliculo-stellate cells in the pars distalis of the pituitary gland in three rodent species.

Ultrastructural features of folliculo-stellate cells of the anterior lobe of the pituitary gland were described in three rodent species (the mouse, guinea pig, golden hamster). These cells are agranular and form the lining of tiny follicles projecting microvilli. Long cytoplasmic expanding processes are intermingled with granular cells of various morphofunctional types without special relationships to one cell type or another. In the guinea pig, the abundance of intermediate filaments appears as a notable feature in the cytoplasm of the folliculo-stellate cells. The results are compared with those previously published.

Ultrastructural identification of folliculo-stellate cells in the pars distalis of the cat and dog pituitary gland.

Ultrastructural features of folliculo-stellate cells of the anterior lobe of the pituitary gland have been described in the cat and dog. These cells are agranular and form the lining of tiny follicles into which microvilli project. Long expanding cytoplasmic processes are intermingled with granular cells of various types without special relationships to one cell type or another. A few features are reported which are peculiar to each species. The results are compared with those previously described.

Cell types of the pars distalis of the hedgehog (Erinaceus europaeus L.) adenohypophysis: cytological, immunocytochemical and ultrastructural studies. 4. Thyrotropic cells.

Staining and histochemical methods, immunofluorescence and electron microscopy were used to individualize the thyrotropic cells in the adenohypophysis of the non-hibernating hedgehog. One cell type was differentiated; its characteristics at the light and electron-microscopic levels were presented. Immunofluorescence has confirmed the functional significance of this cell type and the validity of the denomination of 'thyrotropic cells'.

Cell types of the pars distalis of the hedgehog (Erinaceus europaeus L.) adenohypophysis: cytological, immunocytochemical and ultrastructural studies. 3. Opiocorticomelanotropic cells.

Staining and histochemical methods, immunofluorescence and electron microscopy were used to individualize the opiocorticomelanotropic cells in the adenohypophysis of the non-hibernating hedgehog. One cell type was differentiated; its characteristics at the electron-microscopic level were presented. Immunofluorescence has confirmed the functional significance of this cell type and the validity of the denomination 'opiocorticomelanotropic cells'.

A human beta-endorphin pituitary adenoma.

A beta-endorphin (beta END)-containing pituitary adenoma was demonstrated by immunocytochemical, biochemical, and ultrastructural methods in a 43-yr-old man who had impotence, slight testicular atrophy, and an enlarged sella turcica (grade II0), but no manifestations of Cushing's disease. Preoperative hormone data revealed hyperprolactinemia (97 ng/ml), low plasma cortisol levels without circadian rhythm, undetectable plasma ACTH, and normal plasma FSH and LH levels, with an impaired response to LRH. After hypophysectomy, these hormone levels normalized and responded normally to dynamic tests. Immunocytochemically, 30% of the tumor cells reacted only with beta END antiserum. beta END immunoreactivity was the only component revealed by RIA and sodium dodecyl sulfate-polyacrylamide gel electrophoresis. A characteristic ultrastructural aspect is also described. These findings demonstrate dissociation in the secretion of the proopiomelanocortin-derived peptides and suggest a relationship between hyperprolactinemia and tumor secretion of beta END.

Cell types of the pars distalis of the hedgehog (Erinaceus europaeus L.) adenohypophysis: cytological, immunocytochemical and ultrastructural studies. 2. Prolactin cells.

Staining and histochemical methods, immunofluorescence, and electron microscopy were used to individualize the prolactin cells in the adenohypophyseal pars distalis of the nonhibernating hedgehog. One cell type was differentiated; their characteristics at the light and electron microscopic levels were presented. Immunofluorescence has confirmed the functional significance of this cell type and the validity of the denomination 'prolactin cells'.

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

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.

[Cilia-centriole-Golgi apparatus relationships in the glandular cells of the anterior pituitary of the hedgehog (Erinaceus europaeus L)]. / Relations cil-centriole-appareil de Golgi dans des cellules glandulaires de l'antéhypophyse du Hérisson (Erinaceus europaeus L.).

Antehypophysial somatotropic and prolactinic cells of the Hedgehog have isolated cilia composed by a ring of 9 or 8 double tubules with or without a central tubule; this single cilia is in relation with a basal corpuscule. A granulo-filamentous neck joins the basal corpuscule to the subjacent centriole; from this granulo-filamentous neck accompanying the complex basal corpuscule-centriole, microtubules and striated filaments extend towards the Golgi apparatus. The single cilia, probably of chemoreceptor significance, appears in relation with the Golgi complex, a zone of granule formation.

Morphological and biochemical relationships in 31 human pituitary adenomas with acromegaly.

In 22 pure GH cell adenomas and 9 mixed GH cell-prolactin cell adenomas with acromegaly, we compare the morphological and functional data (secretory activity and granular appearance) with GH levels (radioimmunoassays) in the blood and in the tumor. According to morphological criteria, the secretory activity is marked in 13 cases (Group I), mild in 9 cases (Group II), and weak in 9 others (Group III). The mean values of the plasma GH levels in the 3 groups (80 ng/ml plus or minus 22; 26.5 ng/ml plus or minus 2; and 16.89 ng/ml plus or minus 2 respectively) are significantly different. In 17 densely granulated adenomas and 14 sparsely granulated adenomas, the plasma GH values were very variable. The mean levels of these 2 groups (49.76 ng/ml plus or minus 22 and 41.8 ng/ml plus or minus 7.8 respectively) are not significantly different. The GH concentrations in the tumor were also very variable (358 to 78,900 ng/mg). Their highly significant relationship with the granular appearance is an indirect proof of the granular localisation of GH. We distinguish between 4 functional aspects of the GH cell adenoma which define the different levels of synthesis, storage, and excretion. The secretory activity of the GH adenomatous cell varies with the adenomas and differs from that of the normal cell.

[Description of the folliculo-stellate cells in the anterior hypophysis of the monkey Macacus irus]. / Description des cellules folliculo-stellaires dans l'antéhypophyse du singe Macacus irus

Folliculo-stellar cells are present in the anterior lobe of hypophysis of the monkey Macacus irus. These cells limit strait cavities in which one can observe microvillosites at the apical pole of the cells. The folliculo-stellar cells possess long and thin fibers which insert themselves between different types of granular cells and sometimes extend to the peri-capillar regions. Numerous organelles are present in these folliculo-stellar cells, especially microfilaments.

[Folliculo-stellate cells of the anterior hypophyses of the hedgehog (Erinaceus europaeus L.)]. / Etude des cellules folliculo-stellaires de l'antéhypophyse du hérisson (Erinaceus europaeus L.)

The anterior lobe of the hedgehog pituitary possess folliculo-stellate cells. These agranular (or few granular) cells, connected together by juctional complexes in relation with mitochondria, limit small cavities; at the luminar surfaces, microvillosities projecting in the lumen are seen. The lumina of cavities contain, or not, an electron dense substance, but not remnants of glandular cells. Long slender cytoplasmic processes, extended between adjacent granular cells, takes contact with the basement parenchymatous membrane, where they form a so-called "vascular foot". The cytoplasm of these cells contains a variety of organelles; their development is variable and appears in relation with the functional activity of the cell.

[Identification of two cell types in rat brown fat by electron microscopy]. / Mise en évidence de deux types cellulaires dans le tissu adipeux brun du rat. Etude en microscopie électronique

In the Rat brown adipose tissue, the authors have observed by electron microscopy two different cellular aspects : some cells are more dark, they contain numerous glycogen granules, their mitochondrias are pressed close together and the mitochondrial matrix is darker then the cristae ; in the light cells, the mitochondrias are more sparse and moderately electron dense. The two cellular aspects are also observed on thick sections.