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Biomedical subjects

I Fazekas

Publications and source records attributed to I Fazekas.

At least 37 records · Page 2Linked to original sources
PubMed1981

Ba2+ affects growth hormone and prolactin secretion as well as cell morphology in rat anterior pituitary cultures.

The effects of barium ions (Ba2+) on the release of growth hormone (GH), and prolactin (PRL) and ultrastructural changes accompanying altered hormone secretion in primary cultures of the rat anterior pituitary gland were studied in the presence or absence of calcium ions (Ca2+) in the medium. In four days old cultures previously labelled with 14C-L-leucine radiolabelled PRL release was stimulated in the presence of both Ba2+ and Ca2+, while GH release remained unchanged. In the absence of Ca2+, Ba2+ caused a more marked PRL and a significant GH release. In seven days old cultures, Ba2+ stimulated immunoreactive GH release in the presence of Ca2+ three-fold and a dramatic GH release occurred when Ca2+ was omitted from the incubation medium. Many parenchymal cells contracted profoundly in the presence of Ba2+ without Ca2+ in the incubation medium and the discharge of secretory material was frequent in a number of granular cells that did not contract. The observation on contraction suggests that Ba2+ may activate the microtubular-microfilamentous system in pituitary parenchymal cells.

Animals↗
PubMed1980

Rate of thymidine incorporation and incidence of parenchymal cell division in adult rat hypophyseal cell cultures. Effect of thyroliberin and somatostatin.

Cell suspensions derived from adult rat anterior pituitary glands were cultured for up to eight days. Prolactin immunoreactivity and/or tritiated thymidine incorporation into DNA of cell nuclei were demonstrated in cells with and without thyroliberin (TRH) and somatostatin (SRIF) treatment. It has been established that (a) TRH, which is effective in releasing both thyrotropin and prolactin, may stimulate cell proliferation in other than its target cells; that (b) SRIF has no effect on lactotropic cell proliferation and augments thymidine incorporation into DNA of unidentified cells; that (c) immunoreactive lactotropic cells with tritium-labelled nuclei are present in each culture, independent of hypothalamic hormone treatments.

Animals↗
PubMed1980

Rat intermediate lobe cell groups in suspension culture: morphological and functional characteristics.

Intermediate lobe cells mechanically isolated from adult rat hypophyses were maintained in histiotypic suspension culture. The cells survived as long as six weeks. The proliferation of the connective tissue cells was limited, they did not overgrow the glandular cells. The fine structure of the parenchymal cells in the epithelial spherules of the early cultures was practically identical to that in the intact tissue. The morphological sign of exocytosed secretory material could also be found. In older cultures, cells with light and dark cytoplasm were present. The former gradually degenerated and disappeared, while the latter, forming trabecules, retained their intact fine structure. Immunoactive and bioactive ACTH was detected in the culture medium.

Adrenocorticotropic Hormone↗
PubMed1978

Corticoliberin (CRF) activity of the rat neurohypophysis.

Corticoliberin (CRF) activity of the rat stalk-median eminence region (SME) and neural lobe of the pituitary (NL) was tested in vitro using cultured cells of anterior pituitary. The activity of NL was found to be more than 50% lower than that of SME. The parallelism of dose-response curves suggests that corticotropin releasing substances originating from NL and SME may be qualitatively identical. Thus, neurosecretory cells producing corticoliberin seem to form a continuous neurohemal system consisting of the median eminence, the stalk of the neural lobe.

Adrenocorticotropic Hormone↗
PubMed1978

Monolayer cultures of rat pituitary intermediate lobe: growth and fine structure of epithelial cells.

Rat hypophyseal intermediate lobe cells, partially dispersed by trypsin, were cultivated on an inert surface. The attaching capacity, the growth of the cultures and the fine structure of the epithelial cells developed during cultivation were studied. The majority of the cell groups attached to the inert surface within 72 h after explantation. Epithelial islands developed, with a layer consisting of fibroblast-like cells beginning to form at their periphery. By the end of the second week of cultivation the epithelial islets and fibroblast-like cells formed a monolayer. The epithelial cells survived for five weeks. The granular cytoplasm of the epithelial island cells could be well identified on the phase-contrast microcinematographic frames of the young cultures; both epithelial and fibroblast-like cells divided. The mitotic ability of both cell types could be confirmed by their tritiated-thymidine incorporation, too. In young cultures, the fine-structural features of epithelial cells were practically identical with those of the glandular cells in intact glands. In older cultures, the secretory granules in the epithelial cells were lower in number; the localization of the granules at the periphery was predominating.

Animals↗
PubMed1978

Identification of epithelial cells and fibroblasts in hypophysis intermediate lobe cultures by scanning electron microscopy.

Cell cultures of the rat pituitary intermediate lobe grown for eight days were studied in the scanning electron microscope. The epithelial cells and fibroblasts could be differentiated by the characteristic structures of the cell surface and the cell association features, The epithelial cells were characterized by blebs and rugae, microvilli, and occasionally by some cilia. The surface of the fibroblasts was smooth or bore microvilli. Scanning electron microscopy may provide special information for the characterization of endocrine cell cultures.

Animals↗
PubMed1977

DNA synthesis in immunreactive glandular cells in pituitary intermediate lobe cultures.

Cell suspensions were prepared from adult rat pituitary intermediate lobes and grown in medium TC 199 supplemented with foetal calf serum. 7 or 8 days old cultures were pulse labelled with tritiated thymidine and thereafter processed for immunostaining using an antiserum against a synthetic alpha-1-28-ACTH-analogue. Immunreactivity was mainly confined to epithelial cells, but some spindle-shaped cells were also immunopositive. Thymidine incorporation was observed in some immunpositive cells which shows that cells committed to hormone production may enter the mitotic cycle.

Animals↗
PubMed1975

Proliferation and morphology of ascitic cells as a function of age in cell culture.

Ascitic cells in the logarithmic growth phase increase the accumulation of glycogen particles in the course of explantation into suspension culture, probably due to the increasing arrest of glycogenolytic enzymes. At this age, a part of the cells are capable of restitution by exopinocytosis of the glycogen-containing vacuoles ia formation of cytoplasmic buds. Older cells, taken from the plateau-phase, pass atypical differentiation and ageing, are less capable of hindering the abnormal accumulation of glycogen and the hypervacuolisation. As a consequence, the cells finally degenerate and die.

Animals↗