Ultrastructural reorganization of rat adrenal cortex after whole body hyperthermia

Intracellular reorganization of mouse adrenocorticocytes after single whole body hyperthermia is determined by the two main events: development of the general adaptation syndrome and inhibition of the regeneratory plastic reactions in cells resultant from endotoxication and redistribution of plastic resources between organs and tissues. Stress-induced changes manifest in significant exhaustion of lipid droplets in the adrenocorticocytes of all adrenocortical zones, particularly in the zona fasciculata. Intracellular changes in adrenocorticocytes reflecting the development of regeneratory plastic insufficiency manifest in annular transformation of the nucleoli, segregation of the nucleolonema into granular and fibrillar components, intensification of autophagocytosis, and destructive changes in mitochondria and Golgi complex elements. The most pronounced changes were observed in adrenocorticocytes of the zona reticularis. __________ Translated from Byulleten’ Eksperimental’noi Biologii i Meditsiny, Vol. 145, No. 5, pp. 591–596, May, 2008     

Effects of repeated exposures to xenon on rat adrenal cortex ultrastructure

Xenon has many properties of the ideal anaesthetic and it has been proposed to replace classic volatile anaesthetics. Although some studies demonstrated that xenon does not induce gross morphological changes in major organs, little is known on its possible ultrastructural effects. The present study investigates the subcellular effects of repeated exposures to 70% xenon on rat adrenal cortex in comparison with N2O. Animals were divided into four groups: xenon-exposed, N2O-exposed, sham-exposed and controls. Exposed rats were placed into a sealed cage to breathe the respective gas mixture for 2.5 h/day for a week. Specimens of adrenal cortex for electron microscopy and blood samples for determination of corticosterone plasma levels were taken at the end of the last exposure or one week after the last exposure (recovery). Adrenal cortex from N2O- and sham-exposed rats mainly showed dilation of endoplasmic reticulum, whereas xenon-exposed rats also exhibited several cells with lipid droplets appearing subdivided into smaller droplets, irregular in shape and size. In all experimental groups, corticosterone plasma levels increased in comparison to controls. Both ultrastructural and hormonal changes were not detected anymore after one week from the last exposure. These findings indicate that xenon is able to induce subcellular changes in rat adrenal cortex, mainly at the level of lipid structures. The transient changes induced by xenon suggest that this gas can be regarded as a safer anaesthetic.     

Comparative studies on the effects of aminoglutethimide on hamster and rat adrenal cortex.

Adult female, intact or steroid suppressed hamsters were treated twice daily with 7 mg aminoglutethimide phosphate (AG) for 5 days while intact female rats received 14 mg AG per injection. AG resulted in an increase in adrenal gland weight of both hamster and rat. In the hamster AG had no effect on the amount of lipid droplets while in the rat a slightly higher number of fine lipid vacuoles was seen. In the hamster, enlargement of the gland was due to hyperplasia of the zona reticularis cells while in the rat the number of glomerulosa and fasciculata cells increased. AG had no effect on the adrenal cortex of steroid suppressed hamsters. The serum cortisol level was markedly higher in AG-treated hamsters while the corticosterone level was notably lower in AG-administered rats. In both hamsters and rats, AG-treatment did not change the serum ACTH level. Thus the study demonstrated different responses of the hamster and rat adrenal cortex to AG.     

Ultrastructural reorganization of adrenal cortex in rats exposed to hypoxia and treated with nandrolone

Single and repeated hypoxic exposures induced different ultrastructural changes of varying intensity in adrenocorticocytes of rat adrenal zona fasciculata and zona reticularis. Destructive changes in cells were caused by the antianabolic effect of hypoxia and inhibition of regeneration and plastic processes. Treatment with nandrolone (Nerobolil, Gedeon Richter) diminished this effect and stimulated secretory activity of adrenocorticocytes. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 127, No. 5, pp. 588–592, May, 1999     

Phenobarbital-induced alterations of the rat adrenal cortex

To determine the morpholic changes in adrenocortices induced by chronic phenobarbital therapy, the male rats were orally administered the drug daily for varying periods up to three months. Fine structural changes attributable to the drug included mitochondrial pleomorphism and cavitation, loss of cholesterol ester clefts, reorganization of intracellular lipid, hypertrophy of the agranular endoplasmic reticulum and a juxtapositioning of the agranular endoplasmic reticulum, mitochondria and lipid droplets—all suggestive of an actively secreting cortex. The digitonin-glutaraldehyde reaction suggested an active translocation of free cholesterol from lipid droplets to the mitochondria and agranular endoplasmic reticulum following phenobarbital treatment. Phenobarbital appears to stimulate corticosteroidogenesis due in large part to enhanced hepatic corticoid metabolizing enzymes.     

Ultrastructural analysis of the adrenal cortex in rats after bilateral subdiaphragmatic vagotomy

Electron-microscopic investigation of the zona fasciculata and zona reticularis of the adrenal cortex in rats showed that 7 days after bilateral subdiaphragmatic vagotomy the perinuclear space of the adrenocorticocytes and endothelial cells is widened, the tubules of the smooth cytoplasmic reticulum are dilated, the mitochondria edematous, their cristae reduced, and the number and size of the lipid droplets diminished. After 45 days some mitochondria were starting to undergo myelinization, lipid droplets were aggregating, and electron-translucent vacuoles appeared in them. Vagotomy depresses the function of the adrenocorticocytes of the zona fasciculata and zona reticularis of the rat adrenal cortex.Department of Histology and Embryology, Faculty of Internal Medicine, N. I. Pirogov Second Moscow Medical Institute. (Presented by Academician of the Academy of Medical Sciences of the USSR A. P. Avtsyn.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 83, No. 4, pp. 492–494, April, 1977.     

Ultrastructural effects of immobilization on rat muscle spindles

The ultrastructure of rat muscle spindles was examined after the anterior tibial muscles had been immobilized in a plaster cast. There was an increase in the number of collagen fibrils and external laminae around the outer capsules and in the intracapsular space 2 weeks after immobilization. The changes in the intrafusal muscle fibers within 4 weeks included disorientation of myofilaments. After 6 weeks, Z bands had become disarranged, and there was vacuolar degeneration of the sarcoplasmic reticulum in some fibers. Myelin sheaths of many of the myelinated nerve fibers (especially the thick ones, which were probably sensory nerve fibers) had degenerated within 2 weeks. These results indicate that immobilization of skeletal muscles affects not only extrafusal muscle fibers but also the structure of the muscle spindle.     

Ultrastructural organization of slice cultures from rat visual cortex

Summary We have been studying the fine structural organization of slice cultures prepared from the visual cortex of 6-day-old rats and cultured for 2 weeks using a roller culture technique. Neurons in culture exhibited the characteristic cytological differences between perikarya, axons and dendrites. Neuronal and glial processes formed a dense neuropil with minimal extracellular spaces, and within the neuropil there were numerous synaptic contacts. Both morphological types of cortical synapses, type I (asymmetrical) and type II (symmetrical) could be readily identified in slice cultures. The pattern of synaptic connections in culture was remarkably similar to that observed in normal cerebral cortex: asymmetrical synapses were usually found in contact with dendritic spines, less frequently with dendritic shafts, and never on perikarya, whereas symmetrical synapses were found mostly on perikarya, occasionally on dendritic shafts but never on dendritic spines. Synaptic morphology appeared mature after 2 weeksin vitro and did not show the immature features observed at the time of culture preparation. Taken together with our previous light microscopic studies, these results indicate that cortical slice cultures are organotypically organized and serve as a useful model to study mechanisms of cortical development and plasticity.     

Effects of dietary sodium on dopamine content of rat adrenal cortex

Dopamine occurs in the adrenal cortex and appears to provide maximum tonic inhibition of aldosterone secretion. In the present experiments, the effects of high or low sodium (Na+) intake on concentrations of dopamine in the adrenal cortex of adult male Sprague-Dawley rats were examined. In the first experiment, sham-operated and adrenal demedullated rats were provided with 1.5% NaCl or tap water for drinking for 5 days. In the second experiment, sham-operated and adrenal demedullated rats were fed regular laboratory chow (approximately 0.45% NaCl) or low Na+ chow (0.001-0.005% NaCl) for 5 days. High Na+ intake was attended by dramatic increases in fluid consumption, urine production and Na+ excretion. However, high Na+ intake did not affect levels of dopamine, norepinephrine or epinephrine in the adrenal glands. Approximately 45% of adrenal dopamine but less than 4% of either norepinephrine or epinephrine was localized in the adrenal cortex. In the second experiment, animals fed a diet low in Na+ had a significant reduction in Na+ excretion but levels of adrenal catecholamines were unaffected. Approximately 36% of adrenal dopamine but less than 5% of either norepinephrine or epinephrine was localized in the adrenal cortex. These findings suggest that adrenal cortical dopamine concentrations remain relatively constant in spite of presumed differences in turnover rates of this neurohormone.     

Ultrastructural localization of enkephalin-like immunoreactivity in the rat adrenal medulla

The PAP method was applied to adrenomedullary cells to demonstrate the subcellular localization of ELI. The labeled cell-groups were identified from flat-embedded virbratome sections by light microscopy. Electron microscopy showed that the precipitate was associated with the storage granules of the cells. The number of labeled granules varied greatly from cell to cell. In cells corresponding to those showing heavy staining by light microscopy, all the granules were stained with precipitate. It is suggested that the peptide responsible for the ELI might be released together with the catecholamines.     

Experimental hyaline droplets in the rat adrenal cortex

Summary Hyaline droplets and protein-containing vacuoles were produced in adrenocortical cells of female albino rats by methylandrostenediol administration. The lesions were shown to be invariably negative with the method for alkaline phosphatase, but they showed a varying degree of positive staining with the reactions for acid phosphatase and nonspecific esterases. The denser and more regular droplets tended to exhibit a more regular and stronger enzymatic activity, whereas the lesions of the vacuole type containing a less dense, presumably watery material; those regarded as younger were only faintly, if ever, positive with the methods for acid hydrolases.With the immunohistochemical method the authors were able to demonstrate the presence of homologous plasma proteins within the lesions. Most of the droplets and vacuoles were shown to contain albumin, and some of them could be demonstrated to contain also globulin and fibrin in varying amounts. The simultaneous use of different antibodies labelled with contrasting fluorescent dyes as fluorescein isothiocyanate and lissamine rhodamine B 200, disclosed that most droplets were composed of a mixture of plasma proteins. With that method, it was possible to visualise inhomogeneities in the composition of droplets which largely corresponded to those described previously in preparations stained with conventional histological techniques as well as with some histochemical methods.The authors conclude that this type of intracellular hyaline deposit represents a rather common reaction of adrenocortical cells and that it is comparable to the protein absorption droplets, phagosomes and their subsequent developmental stages known in other organs, thus being related to the pinocytotic-lysosomal system of the adrenocortical cell.

---

Experimentelle hyaline Tropfenbildung in der Nebennierenrinde der RatteImmunhistochemische und enzymhistochemische Untersuchungen

Zusammenfassung Durch Verabreichung von Methylandrostenediol entstanden hyaline Tröpfchen und eiweißhaltige Vacuolen in Nebennierenrindenzellen bei weiblichen weißen Ratten. Die cytoplasmatischen Ablagerungen zeigten keine positive alkalische Phosphatasereaktion bei entsprechenden Färbungen, jedoch eine positive Farbreaktion bei saurer Phosphatase und unspezifischer Esterase. Die dichteren und regelmäßigeren Tröpfchen wiesen eine gleichmäßigere und kräftigere Fermentaktivität auf. Dagegen enthielten die vacuolären Ablagerungen wasserhaltige Substanzen. Die als frischer abgefaßte Ablagerungen war enauf saure Hydrolasen schwach positiv. Mit immunohistologischen Methoden konnte man nachweisen, daß sie homologes Plasmaeiweiß enthielten. In den meisten Vacuolen fanden sich ausschließlich Albumine, einige enthielten jedoch auch Globuline und Fibrin in unterschiedlicher Menge Die gleichzeitige Verwendung von verschiedenen, mit FITC und LRB 200 markierten Antikörpern erbrachte den Nachweis, daß die Tröpfchen aus einer Plasma-Eiweiß-Mischung bestanden. Durch die immunohistologische Methode wurde deutlich gemacht, daß die Tröpfchen nicht homogen sind. Man darf annehmen, daß die intracellulären hyalinen Ablagerungen eine gewöhnliche Reaktion der Nebennierenrindenzellen darstellt, die mit den Eiweiß-resorption-Tröpfchen, Phagosomen und deren weiteren Entwicklungsstadien wie sie in anderen Organen vorkommen, vergleichbar sind. So werden diese Gebilde mit dem pinocytär-lysosomalen System der Nebennierenrindenzelle in Bezug gebracht.

     

Ultrastructural effects of riboflavin deficiency on rat hepatic mitochondria

The hepatic mitochondria of rats fed a riboflavin-deficient diet were examined by electron microscopy. Discoidal mitochondria with elongated cristae increased in frequency from day 4 to day 12 of the test diet. At day 22, sheaves of closely packed cristae were present in many otherwise typical mitochondria. At day 53, numerous cupshaped mitochondria appeared; these often nested one inside the other. From this day onward, the mitochondria showed a tendency towards increasing size. By day 82, some had a diameter greater than 8 μm. These and other, smaller mitochondria often contained extremely prominent matrix granules. The production by riboflavin-deficiency of giant mitochondria in the rat liver appears to be unrelated to their capacity to carry out oxidative metabolism.     

The effect of zinc deficiency on the ultrastructure of rat adrenal cortex

The adrenal cortex of male Sprague-Dawley weanling rats maintained on a zinc-deficient diet was studied by electron microscopy. There was a gradual increase in lipid droplets in the zona fasciculata which was quite marked at 7 weeks, but increased lipid was not observed in the zona glomerulosa or reticularis of zinc-deficient rats. The adrenal cortex of the control animals did not show altered lipid content. A possible explanation for the effect of zinc deficiency on the adrenal cortex is offered.     

Expression of intermediate filament proteins in adrenal cortex and related tumours

The intermediate filament profile of adrenal cortex and its related tumours has been evaluated. Most adrenocortical cells contained cytokeratin 8 and 18 as demonstrated by monoclonal antibodies CAM 5.2, M20, M9 and RGE53. Cytokeratin immunoreactivity was not confined to a functional zone of the adrenal cortex. Only a small number of the adrenocortical cells showed vimentin immunoreactivity. From normal adrenal cortex through adenomas, to carcinomas, there is a progressive decrease or even loss of cytokeratin immunoreactivity and an increase in vimentin immunoreactivity. Aberrant cytokeratin expression was not found in adrenocortical adenomas and carcinomas with the antibodies used. Awareness of the possible absence of cytokeratin immunoreactivity in adrenocortical carcinomas is important whenever antibodies to cytokeratins and vimentin are used for diagnostic purposes in poorly differentiated neoplasms.