On the fine structure of alteration of the adrenal cortex in hypophysectomized rats

High-Resolution Tissue Mass Spectrometry Imaging Reveals a Refined Functional Anatomy of the Human Adult Adrenal Gland

In the adrenal gland, neuroendocrine cells that synthesize catecholamines and epithelial cells that produce steroid hormones are united beneath a common organ capsule to function as a single stress-responsive organ. The functional anatomy of the steroid hormone-producing adrenal cortex and the catecholamine-producing medulla is ill defined at the level of small molecules. Here, we report a comprehensive high-resolution mass spectrometry imaging (MSI) map of the normal human adrenal gland. A large variety of biomolecules was accessible by matrix-assisted laser desorption/ionization-Fourier transform-ion cyclotron resonance MSI, including nucleoside phosphates indicative of oxidative phosphorylation, sterol and steroid metabolites, intermediates of glycolysis and the tricarboxylic acid cycle, lipids, and fatty acids. Statistical clustering analyses yielded a molecularly defined adrenal anatomy of 10 distinct molecular zones including a highly structured corticomedullary interface. By incorporating pathway information, activities of carbohydrate, amino acid, and lipid metabolism as well as endocrine bioactivity were revealed to be highly spatially organized, which could be visualized as different molecularly defined zones. Together, these findings provide a molecular definition of human adult adrenal gland structure beyond classical histological anatomy.

Evidence that an extrahypothalamic pituitary corticotropin-releasing hormone (CRH)/adrenocorticotropin (ACTH) system controls adrenal growth and secretion in rats

Within two weeks, hypophysectomy induced in rats a striking decrease in the level of circulating ACTH (the concentration of which was at the limit of sensitivity of our assay system), coupled with a net reduction in the plasma corticosterone concentration and an evident adrenal atrophy. Zona fasciculata, the main producer of glucocorticoids, was decreased in volume, due to a lowering in both the number and average volume of its parenchymal cells. Subcutaneous ACTH infusion (0.1 pmol.min-1), administered during the last week following hypophysectomy, restored the normal blood level of ACTH and completely reversed all effects of hypophysectomy on the adrenals. Subcutaneous infusion for one week with alpha-helical-CRH or corticotropin-inhibiting peptide (1 nmol.min-1), which are competitive inhibitors of CRH and ACTH, evoked a further significant lowering of plasma corticosterone concentration and markedly enhanced adrenal atrophy in hypophysectomized rats. These findings strongly suggest that an extrahypothalamic pituitary CRH/ACTH system may be involved in the maintenance of the growth and steroidogenic secretory activity of the rat adrenal cortex.

Spontaneous or experimentally induced formation of a special zone in the adrenal cortex of the adult brush-tailed possum (Trichosurus vulpecula)

The cytology and ultrastructure of the hypertrophied special zone, which is formed spontaneously in the adrenal cortex of adult female brush-tailed possums (Trichosurus vulpecula), was compared to the adrenocortical tissue in adult males in which the special zone, normally absent, was induced following castration alone or by additional treatment with follicle-stimulating hormone (FSH). The special zone in females was situated between the zona fasciculata and the zona reticularis, the latter being a rudimentary zone in this species. Special zone tissue extended as a broad band parallel to and on one side of the adrenal medulla. In the luteal phase of the reproductive cycle, the special zone cells showed ultrastructural features commonly associated with steroidogenic tissues, with many mitochondria and compact masses of smooth endoplasmic reticulum. Cytoplasmic lipid inclusions were rarely observed. In lactating females, however, the special zone cells exhibited cytological and ultrastructural features suggestive of a transformation in their morphology broadly divided into two types of cells: (1) cells at the periphery of the special zone (closest to the zona fasciculata) showed variable quantities of lipid inclusions, mitochondria with dispersed cristae, and segregation of the smooth endoplasmic reticulum into compact masses; (2) cells within the more central regions showed an increasing abundance of lipid inclusions which in many cells became the dominant feature of the cytoplasm. These special zone cells contained very little smooth endoplasmic reticulum and their mitochondria contained few cristae together with amorphous granular material within the matrix. In castrated males, special zone tissue developed between the zona fasciculata and the zona reticularis, appearing initially as focal islands of cells (8 months postcastration) and later (11 months postcastration) expanding into a single zone, probably via the proliferation and differentiation of adjacent cells of the zona fasciculata and longitudinal growth of the special zone. Similar focal aggregations of special zone cells were induced after 14 days of FSH treatment given to 2-month castrated males. In all castrated and FSH-treated castrated males, the ultrastructure of special zone cells was similar to that of special zone cells in luteal-phase female possums. The findings suggest that the formation and cellular composition of the special zone is associated with changes in the pituitary-gonadal axis and that FSH plays a primary role in the differentiation of this tissue.

Serum ACTH and adrenal histology in reproductively inhibited male prairie deermice (Peromyscus maniculatus bairdi)

Exogenous ACTH will cause adrenal hypertrophy and gonad dysfunction in reproductively capable male deermice. The ultrastructure of the zona fasciculata of inhibited animals is substantially different from ACTH stimulated animals which suggests that ACTH alone does not produce the inhibition. Although ACTH concentrations were variable, there was no clear demonstration that any differences existed between reproductively capable vs inhibited animals at the time when corticosterone is known to be elevated in the inhibited animals. A contributory role for ACTH in promoting inhibition is not ruled out, but neither is it likely that elevated ACTH alone accounts for the observed reproductive inhibition in animals taken from populations.

Sex dimorphism of the adrenal cortex in rats after treatment with dexamethasone

Sex dimorphism of adrenal cortex of the rat was studied by light and electron microscopy as well as the karyometric, gravimetric, and histometric methods after treatment with dexamethasone (2.0 mg/kg over a period of 4 days). Sex dimorphism cannot be shown in dexamethasone-induced atrophy of adrenal glands. Male fasciculata cells have more and finer distributed liposomes resembling in this way female fasciculata cells. Normally present differences in adrenal weight and nuclear size of fasciculata cells between both sexes disappear; nevertheless, female fasciculata cells remain relatively bigger compared to the corresponding male cells. Annulment of sex dimorphism is thought to be the result of altered functional activity of the zona fasciculata due to failing pituitary stimulation. Higher secretion activity of female fasciculata cells probably ceases after dexamethasone treatment.

Fine structural and biochemical effects of aminoglutethimide and o,p'-DDD on rat adrenocortical carcinoma 494 and adrenals

Rats bearing adrenocortical carcinoma 494 were injected daily for 7, 14, or 21 days with aminoglutethimide (AG) or o,p'-DDD. Reversibility of these steroidogenic inhibitors was determined by injecting other animals for either 14 or 21 days and sacrificing them 14 days later. While the drugs had little effect on body or tumor growth, plasma corticosterone levels were reduced a maximum of 88% in normal and 95% in tumor-bearing rats during AG chemotherapy. These levels were unaltered in normal rats by o,p'-DDD and reduced a maximum of 64% in tumor-bearing animals. Relative adrenal weights generally increased during chemotherapy and then returned to control levels. These changes were mainly due to alterations in the lipid and mitochondrial volume fractions. Lipid increased with both drugs while mitochondria increased with o,p'-DDD and decreased with AG. Cholesterol ester levels paralleled the lipid stereology more closely with AG than o,p'-DDD. With both drugs the most notable changes in tumor fine structure was a decrease in mitochondrial internal membranous vesicles and matrical density. Adrenal mitochondria had the irregular, elongated forms characteristic of tumor-bearing animals and were vacuolated (AG) or had internal rings (o,p'-DDD). The large lipid droplets observed during chemotherapy with both drugs were replaced by numerous small droplets in recovery periods.

Electron microscopic studies of the effect of ACTH and flavin-adenine dinucleotide on adrenocortical atrophy of rats treated with dexamethasone phosphate

In a previous paper the authors described the morphologic observations that the concomitant administration of ACTH and flavin-adenine dinucleotide (FAD) to hypophysectomized rats exerted a more potent preventive effect on atrophy of the adrenal cortex of the animals than the single administration of ACTH. The present study was made to electron-microscopically observe the effect of concomitant administration of ACTH and FAD on atrophy of the adrenal cortex induced with the administration of dexamethasone (Dx). The zona fasciculata of the adrenal gland of rats treated with Dx+ACTH+FAD was morphologically closer in cell organelles such as smooth-surfaced endoplasmic reticulum, mitochondria and chylomicrons to that of control animals than the counterpart of animals treated with Dx+ACTH only. The zona fasciculata of the adrenal cortex of animals treated with Dx+FAD was morphologically similar to that of animals treated with Dx only. These findings suggested that FAD would potentiate the adrenocorticotropic action of ACTH through its physiologic action.

Electron microscopic study of the response of the adrenocortical X-zone in mice treated with sex steroids

In the adrenal cortex of 23- to 27-day-old C3H/Tw female mice, the eosinophilic X-zone became increasingly increasingly undetectable after 3 injections of 100 microgram testosterone propionate (TP). Whorls of smooth endoplasmic reticulum (sER) and peculiar complexes of mitochondria and sER, characteristics of X-zone cell, were no longer present in mice given 7 daily injections of TP. The ordinary mitochondria, although reduced in number, became swollen and actually increased in percent area occupied. They had well-developed tubulovesicular cristae. The lipid droplets increased in size and number after 3 daily TP injections, but decreased after 7 daily injections. Rough endoplasmic reticulum and sER were reduced in area in mice receiving 7 daily injections. The X-zone also became indistinguishable from the zona fasciculata after 7 daily injections of 5alpha-dihydrotestosterone propionate. Injections of progesterone or estradiol-17 beta had no effect on the X-zone.

Involutive morphological modifications in the rat adrenal glomerular zone after a low-sodium diet

We have studied glomerular zone involution in the rat's adrenal gland after a period of hyperfunction brought about by a low-sodium diet. The changes observed in this zone effect those organoids that are more directly involved in steroid genesis; mitochondria, smooth endoplasmic reticulum and liposomes. The Golgi complexes appear very developed, often, showing, a positive acid phosphatase activity. Lysosomes suffered a considerable increase in their number, and carried out their digestive function on liposomes. All those changes discussed here are seen as an accomodation of this zone to the new normofunctional situation.

Electron microscopic studies on the effect of ACTH and flavin adenine dinucleotide on adrenocortical atrophy of hypophysectomized rat

Electron microscopic observation was made on the outer fasciculata cells in the adrenal cortex of hypophysectomized rats receiving 10 mg of FAD and/or 0.3 mg of ACTH intraperitoneally once a day for 5 consecutive days from 24 hours after hypophysectomy. The simultaneous administration of FAD and ACTH to the hypophysectomized rat was more effective for preventing adrenocortical atrophy induced than the administration of ACTH alone. This effect appeared as clear cells with low electron density. While the characteristics induced by hypophysectomy were the decrease in number of smooth-surfaced endoplasmic reticulum (SER) and mitochondria and also crista of mitochondria being tubular. The clear cells showed a less degree of their characteristic. From this fact, it is considered that the external FAD acts against fasciculata cells in the adrenal cortex of hypophysectomized rats as a coenzyme for flavin enzyme under ACTH and decreases oxidation-reaction in mitochondria and oxidative phosphorilation reaction in SER, being induced by hypophysectomy.

Fine structure of a virilizing adrenocortical adenoma

An adrenocortical adenoma associated with adrenogenital syndrome in a two-year-old boy was investigated light and electron microscopically. Urinary 17-ketosteroid excretion was considerably elevated and unresponsive to dexamethasone administration. The level returned to normal after surgical removal of the tumour. Adenomatous cells display striking cellular and nuclear pleomorphism. Megalocytes with huge nuclei and nucleoli frequently occur. Deep cytoplasmic indentations cause nuclear pseudoinclusions and bizarre shape of the nuclei. True nuclear inclusions are also seen, as well as nuclear fragmentation. Cytoplasmic organelles show striking morphological alterations. Mitochondria with lamellar and tubular cristae are transformed into round or ovoid organelles of vesicular type. Their internal compartment is reduced, matrix material increases relatively, and mitochondrial inclusion bodies develop. Mitochondrial inclusions are identified as corresponding to fuchsinophil (siderophil or argyrophil) granules seen in the light microscope. Their staining properties indicate their glycoprotein nature. Vesicular profiles of smooth endoplasmic reticulum predominate and stacks of rough endoplasmic reticulum are transformed into tubules and vesicles. In Golgi regions, only vesicular elements are enriched. Lipid droplets are scarce. It was not possible to demonstrate histochemically catalase activity in microbodies. Dense bodies only occur in small, undifferentiated tumour cells. Multivesicular bodies, autophagosomes and residual bodies are rare. Lipofuscin is absent. Tumour cells are thought to derive from a population of undifferentiated cells ("germinative tumour cells"). Their morphological features and organelle equipment during a hypothetical course of differentiation and following dedifferentiation is described and discussed with respect to exceeding androgen synthesis.