Browsing by Subject "ACTH"

Now showing 1 - 2 of 2
  • Thumbnail Image
    Publication
    Open Access
    ACTH-induced ultrastructural changes in the zona fasciculata of the hamster adrenal cortex. Are intraadrenal thrombi regulators of corticosteroid secretion?
    (Murcia : F. Hernández, 1992) Ginda, Waclaw J.; Warchol, Jerzy B.; Malendowicz, L.K.
    Correlated stereological and functional studies were performed on the effect of massive ACTH doses on adrenal cortex of the female hamster. ACTH resulted in a marked increase in adrenal gland weight at day 6 of treatment followed by a drop at day 9. Stereology showed significant enlargement of the zona fasciculata (ZF) cells with the highest value at day 6 and subsequent drop at day 9 of treatment. This hypertrophy was due to a notable increase in the volume of mitochondrial, SER, Golgi apparatus and lipid droplet compartments. Cortisol secretion by adrenal slices and homogenates was also highest at day 6 of ACTH administration and notably lower at day 9. At day 6 of ACTH treatment in outer ZF thrombi were seen. In their vicinity the subendothelial space was dilated and endothelial cells dissociated from the basa1 lamina. Numerous erythrocytes were also visible among dissociated ZF cells. At day 9 of experiment in outer part of ZF numerous spaces devoid of parenchymal cells appeared. The earlier authors considered the «empty spaces» or «holes» in hyperstimulated adrenal cortex as-a sign of holocrine secretion of steroid hormones. The present findings enable us to introduce a new hypothesis on the development of these spaces. In our opinion in hyperstimulated adrenal cortex numerous thrombi may be formed leading thus to the degeneration of adrenocortical cells. Thus, the appearance of the aempty spaces» or «holes» in the gland is not connected with the holocrine secretion but with the regulation of the number of secretory cells in adrenal cortex by the thrombi-dependent mechanism. A similar mechanism may also be responsible for the remodelling of the gland after its enlargement due to ACTH administration.
  • Thumbnail Image
    Publication
    Open Access
    Proliferation and distribution of adrenocortical cells in the gland of ACTH- or dexamethasone-treated rats
    (Murcia : F. Hernández, 1990) Stachowiak, A.; Nussdorfer, G.G.; Malendowicz, L.K.
    The effects of prolonged (7-day) ACTH and dexamethasone administrations on rat adrenocorticalcell turnover have been investigated by combined stereological and metaphase-arrest techniques. ACTH was found to increase the number of parenchymal cells in each adrenal zone; however, ACTH altered the cell distribution in the cortex, lowering their percentage in the zona glomerulosa (ZG) and zona fasciculata (ZF) and enhancing it in the zona reticularis (ZR). The cell birth-rate was markedly raised by ACTH exclusively in ZG and ZF. Dexamethasone notably decreased the number of ZF and ZR cells, without altering that of ZG cells. Moreover. dexamethasone increased the percentage of parenchymal cells in ZG and ZF, and lowered it in ZR. In the adrenal cortices of dexamethasoneadministered animals, metaphases were virtually absent. These data indicate that ACTH increases the cell birthrate in ZG and possibly ZF, and enhances the centripetal migration of newly-formed cells and their accumulation in ZR. Dexamethasone inhibits both proliferation of adrenocortical cells in the outer cortical layers and their centripetal migration into ZR. Moreover, it appears to cause parenchymal-cell loss in the inner adrenocortical layers.