Electron Microscopy and Morphometry of Nucleoli in Rat Neurosecretory Cells with Stimulated and Suppressed Secretion

Abstract

The nucleoli in the neurons of the supraoptic nucleus in the rat were analyzed by electron microscopy and morphometry after the secretion of vasopressin had been fully suppressed by water load, after the secretion had been stimulated by water deprival and in normal rats which had water ad libitum. Suppression of the secretion increased the proportion of fibrillar centres in the nucleoli 2-fold. Stimulation of the secretion increased the proportion of the granular component by 22%. The overall nucleolar organization did not change very much with the secretory activity. The results show that an increased proportion of fibrillar centres in nucleoli is an indicator of decreased secretory activity and, moreover, that an increased volume of the nucleolar fibrillar and granular components per cell indicates an increased secretory activity.

A Morphometric Analysis of Nucleoli in Cultured Carcinoma Cells of the Human Thyroid

“…The density of FC was larger in TCC − than in TEC − . This indicates a lower level of protein synthesis [1], just as the observed higher density of the fibrillar component and the lower of the granular component does. These observations indicate that TCC in culture have a lower level of protein synthesis than TEC and do not respond to TSH stimulation.…”

“…TSH decreased the density of the fibrillar component and increased that of the granular component. These changes are seen in other cellular systems in which protein synthesis is stimulated [1,9,20]. Thyrocytes in secondary monolayer culture preserve the ability to produce thyroglobulin (TG) and to react to TSH-stimulation [18].…”

“…The primary objective of the present investigation is to determine whether the size and number of NORAP accumulations in malignant cells differed from those of non-malignant cells. In normal cells, stimulation of the secretion influences the content of the nucleolar components [1,9,20]. The secondary objective was to investigate to what extent the content of the fibrillar and granular components differs between thyroid epithelial cells (TEC) and thyroid carcinoma cells (TCC) and the influence of TSH on both sets of samples.…”

Accessory groups of nonapeptidergic neurosecretory cells of the hypothalamus and adjacent regions of the brain in rats under conditions of dehydration

“…The nucleolus in NSC plays an exceptional role in the synthesis of ribonucleoproteins, and karyometry is still widely used for assessing the function of NSC [8]. The animals were decapitated on days 2 and 8 of the experiment.…”

Morphological and functional aspects of neurosecretory process in hypothalamic nuclei in heart failure

“…Они находятся в состоянии функционального торможения (депонирования), принимая при этом пикноморфный вид [2,6]. Данное состояние нейроцитов целесообразно обозначить, условно, в качестве 5-й фазы [8,9]. Целью исследования является выяснение процентного соотношения клеток, имеющих признаки различных фаз нейросекреции в «норме» и при патологии, а также выяснение уровня функциональной активности ядер.…”