Abstract
The fine structure of the different zones in the adrenal cortex of the adult rat has been studied under the electron microscope. Four regions mainly differentiated by the mitochondrial morphology, the lipid droplets, and the structure of the ground cytoplasm were recognized. In the glomerular zone mitochondria are thin and elongated with an abundant matrix. The inner structure is characterized by the presence of tubules of 300 A that are straight or bend at an angle and which may be grouped in parallel array giving a pseudocrystalline pattern. The wall of each tubule is a finger-like projection of the inner membrane and its cavity corresponds to the outer chamber of the mitochondrion. In the intermediary zone mitochondria are larger and irregular. The matrix is filled with convoluted tubules and vesicular elements. The lipid droplets are larger and irregular in the glomerulosa and and small in the intermedia. The ground substance is dense and contains free ribosomes in the glomerulosa and starts to be vacuolated in the intermedia. In the fasciculata mitochondria are round or oval and are filled with vesicular elements with a mean size of 450 A. Larger vesicles and more clear elements (vacuoles) are seen near the edge as if their content was diluted. Some of these vacuoles protrude on the surface. In the reticular zone mitochondria are also vesicular but frequently show signs of alteration and disruption. Dense elements recognized as microbodies are observed in the fasciculata but they increase in number in the reticularis. These results are discussed on the light of the so called zonal theory of the adrenal cortex. Two stages in the differentiation of the mitochondria are postulated. The tubular structure of the glomerulosa undergoes a process of disorientation and dilatation of the tubules to form the tubulo-vesicular elements of the intermediary zone. In a second stage of differentiation, by fragmentation of the tubules, the vesicular structure of fasciculata is formed. These findings are discussed from the viewpoint of the relationship between mitochondria and synthesis of steroid hormones. A secretory process that starts within mitochondria by the formation of vesicles and proceeds into the ground cytoplasm, as extruded and more clear vacuoles, is postulated.
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Selected References
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- BELT W. D., PEASE D. C. Mitochondrial structure in sites of steroid secretion. J Biophys Biochem Cytol. 1956 Jul 25;2(4 Suppl):369–374. [PMC free article] [PubMed] [Google Scholar]
- BENNETT H. S., LUFT J. H., HAMPTON J. C. Morphological classifications of vertebrate blood capillaries. Am J Physiol. 1959 Feb;196(2):381–390. doi: 10.1152/ajplegacy.1959.196.2.381. [DOI] [PubMed] [Google Scholar]
- Baxter J. S. The growth cycle of the cells of the adrenal cortex in the adult rat. J Anat. 1946 Jul;80(Pt 3):139–146.3. [PMC free article] [PubMed] [Google Scholar]
- DE ROBERTIS E., SABATINI D. Mitochondrial changes in the adrenocortex of normal hamsters. J Biophys Biochem Cytol. 1958 Sep 25;4(5):667–668. doi: 10.1083/jcb.4.5.667. [DOI] [PMC free article] [PubMed] [Google Scholar]
- GREEP R. O., DEANE H. W. The cytology and cytochemistry of the adrenal cortex. Ann N Y Acad Sci. 1949 Jun 27;50(ART):596–615. doi: 10.1111/j.1749-6632.1949.tb39869.x. [DOI] [PubMed] [Google Scholar]
- LEVER J. D. Cytological studies on the hypophysectomized rat adrenal cortex: the alterations of its fine structure following ACTH administration and on lowering the Na/K ratio. Endocrinology. 1956 Feb;58(2):163–180. doi: 10.1210/endo-58-2-163. [DOI] [PubMed] [Google Scholar]
- LEVER J. D. Electron microscopic observations on the adrenal cortex. Am J Anat. 1955 Nov;97(3):409–429. doi: 10.1002/aja.1000970304. [DOI] [PubMed] [Google Scholar]
- LUFT J., HECHTER O. An electron microscopic correlation of structure with function in the isolated perfused cow adrenal, preliminary observations. J Biophys Biochem Cytol. 1957 Jul 25;3(4):615–618. doi: 10.1083/jcb.3.4.615. [DOI] [PMC free article] [PubMed] [Google Scholar]
- PALADE G. E. An electron microscope study of the mitochondrial structure. J Histochem Cytochem. 1953 Jul;1(4):188–211. doi: 10.1177/1.4.188. [DOI] [PubMed] [Google Scholar]
- STACHENKO J., GIROUD C. J. Functional zonation of the adrenal cortex: pathways of corticosteroid biogenesis. Endocrinology. 1959 May;64(5):730–742. doi: 10.1210/endo-64-5-730. [DOI] [PubMed] [Google Scholar]
- TONUTTI E., BAHNER F., MUSCHKE E. Die Veränderungen der Nebennierenrinde der Maus nach Hypophysektomäe und nach ACTH-Behandlung, quantitativ betrachtet am Verhalten der Zellkernvolumina. Endokrinologie. 1954;31(5):266–284. [PubMed] [Google Scholar]