The stereological structure of rat adrenal gland was analysed by light and electron microscopy after an acute (60 min) exposure to high ambient temperature (38°C). Under these conditions a significant increase in plasma corticotrophin (ACTH), serum corticosterone and aldosterone levels were observed. Histological and stereological investigation at light microscopy showed significant decrease in volume density of capsule and zona glomerulosa, increase in volume of fasciculata cells, and decrease of numerical density of zona fasciculata cells and mean diameter of blood vessels. At the ultrastructural level, volume density of nuclei and mitochondria of zona glomerulosa cells were significantly increased and that of lipid droplets decreased. Volume density of mitochondria of fasciculata cells was significantly increased, while number of lipid droplets per µm2 of cell was reduced. In the cells of zona reticularis significant increase in the number of lipid droplets was found. The response of zona glomerulosa may be interpreted as immediate reaction to dehydration, while alterations detected in zona fasciculata, which were less extensive, were related to purely stressogenic effects of high ambiental temperature.
Isolated rat adrenal medulla was analyzed by light and electron microscope after an acute (60 min) exposure to high ambient temperature (38°C). Under these conditions there was a significant rise in plasma adrenaline and noradrenaline. Stereological investigation by light microscopy showed a significant decrease in volume density of cells and an increase in the interstitium. At the ultrastructural level, the profile area of cells, nuclei and cytoplasm of adrenaline cells were significantly decreased. After the heat stress numbers of resting granules in adre naline and noradrenaline cells were significantly reduced, while the numbers of altered granules and empty containers in both types of adrenomedullar cells were significantly increased.
Andropause, the culminating phase of male ageing, is characterized by deregulation of the hypothalamic-pituitarygonadal axis and low circulating free testosterone. The aim of this study was to investigate the immunohistomorphometric characteristics of the pituitary gonadotropic i.e. follicle-stimulating hormone (FSH) and the luteinizing hormone (LH) producing cells after testosterone application in a rat model of the andropause. Middle-aged Wistar rats were divided into orchidectomized (ORX; n=8) and testosterone treated orchidectomized (ORX+T; n=8) groups. Testosterone propionate (5 mg/kg b.m./day) was administered for three weeks, while the ORX group received the vehicle alone. Immunohistochemically stained FSH and LH cells underwent morphometric and optical density-related analysis, while circulating concentrations of the sex steroids were measured by immunoassays. Serum concentrations of testosterone and estradiol were significantly (p<0.05) increased by 24 and 2.7 fold respectively, compared to the ORX group. The volume of FSH and LH cells was significantly (p<0.05) decreased by 51.3% and 56.6% respectively, in comparison with ORX rats. Relative volume density of FSH and LH cells was also significantly (p<0.05) decreased by 54.0% and 72.8% respectively, compared to the ORX group. Results related to the optical density of gonadotropic cells (reflecting their hormonal content) were in line with the morphometric findings i.e. this parameter of FSH and LH cells was significantly (p<0.05) decreased by 25.7% and 16.2% respectively, in comparison with ORX rats. Conclusion: In conclusion, applied testosterone increased the serum concentrations of sex steroids, as well as it decreased morphometric parameters and optical density of gonadotropic cells in ORX rats.
Hyperthermia can cause significant structural and functional reorganization of tissues and organs. The proliferative and apoptotic processes of rat adrenal cortex were analyzed by light and electron microscopy after an acute exposure to high ambient temperature. Animals were divided in two groups. The first group consisted of intact controls. The rats from the second group were exposed to a high ambient temperature of 38°C for 60 min. Mitotic chromosomes and the largest number of immunoreactive nuclei for the Ki-67 were observed in the zona reticularis (ZR) of the control animals. The relative number of mitoses after heat stress showed a significant decrease in the zona glomerulosa (ZG; 66.8%), zona fasciculata (ZF; 27.8%) and ZR (86.7%) (for all zones p<0.05), while in the whole adrenal cortex the after-treatment decrease was 61.9% (p<0.05) compared to the controls. Under heat stress numerous apoptotic nuclei were seen at the light and ultrastructural levels in all the zones of the adrenal cortex. Such dynamics of mitosis/apoptosis events seriously affect adrenal cortex morphology. [Projekat Ministarstva nauke Republike Srbije, br. 173023 i br. 173009
Immunohistochemistry revealed the presence of VIP-, NPY- and SP-immunoreactivity in the rat adrenal medulla. VIP- and NPY-immunoreactivity was detected in chromaffin and ganglion cells and in nerve fibers, but SP-immunoreactivity was found only in chromaffin cells. After acute heat stress, VIP- and NPY- immunoreactivities in cells and nerve fibers were reduced, probably as a result of the release of these peptides with catecholamines. The absence of SP-immunoreactive ganglion cells in the adrenal medulla suggests that the SP-immunoreactive nerve fibers are extrinsic in origin
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