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[Androgen secreting adrenal cortex tumors].

Endokrine active tumours of the adrenal cortex are rare diseases in man. Benign as well as malignant tumours of the adrenal cortex can alone excrete cortisol, aldosterone, androgens or oestrogens. More frequent are, however, tumours with a mixed incretion. Publications about tumours forming sexual hormones are above all descriptions of individual cases. After a short explanation of the most important clinical, diagnostic and therapeutic aspects on androgen-producing tumours of the adrenal cortex four own cases are discussed.

Adrenal Cortex Neoplasms↗

A comparison of the low-density-lipoprotein receptor from bovine adrenal cortex, rabbit and rat liver and adrenal glands by lipoprotein blotting.

This paper describes the use of lipoprotein blotting to detect low-density-lipoprotein (LDL) receptors in rat and rabbit liver and adrenal glands and in bovine adrenal glands. Using this technique we show that the rabbit and rat liver LDL receptors have Mr values of 128000 and 145000 respectively. Mr values for the rabbit, rat and bovine adrenal receptors are 131000, 142000 and 132000 respectively. Differences between the bovine adrenal and rat liver receptors are not due to differences in the degree of sialylation. Lipoprotein blotting can be used to detect dietary- and drug-induced changes in the concentrations of LDL receptors. When rabbits are fed on a cholesterol-rich diet, liver LDL receptors cannot be detected, consistent with the suppression of hepatic LDL receptors by cholesterol feeding. Pharmacological doses of 17 alpha-ethinyloestradiol cause a marked increase in hepatic LDL-receptor activity in the rat. This is accompanied by a corresponding increase in the number of LDL receptors detected by lipoprotein blotting. The Mr of the induced receptor is identical with that of the receptor from control rats, which suggests that the induced receptors are produced by the same gene as LDL receptors normally present in the liver.

Adrenal Cortex↗

Impaired pregnenolone biosynthesis in adrenal cortex mitochondria by adriamycin.

Adrenal cortex mitochondria isolated from mongrel dogs were incubated with cholesterol in the presence and absence of adriamycin (ADM). The capacity for cholesterol side chain cleavage was assessed by determining the pregnenolone yield. ADM behaves as an inhibitor of pregnenolone biosynthesis with a calculated IC50 of 110 microM. The inhibitory effect follows a dose-response relationship depending upon ADM concentration.

Adrenal Cortex↗

Iron exclusion by proliferative foci and neoplastic lesions induced by 7,12-dimethylbenz(a)anthracene in the rat adrenal cortex.

Proliferative and neoplastic adrenal cortical lesions were produced in female Sprague-Dawley rats by 7,12-dimethylbenz(a)anthracene. These lesions were studied for their ability to store histochemically demonstrable cellular iron compared with normal adrenocortical cells following iron loading by subcutaneous injection of iron-dextran. Stainable iron was excluded, under conditions in which normal cortical cells were heavily loaded with iron, in three histological types of adrenal cortical lesions; eosinophilic and basophilic proliferative foci; adenomas and lesions transitional between foci and tumours. The property of iron exclusion may be useful in studying neoplastic development in the adrenal gland.

9,10-Dimethyl-1,2-benzanthracene↗

Demonstration of glucocorticoid receptors in the adrenal cortex: evidence for a direct dexamethasone suppressive effect on the rat adrenal gland.

The adrenal cortex was evaluated for the presence of glucocorticoid receptors and functions. Substantial binding of [3H]dexamethasone was observed in aminoglutethimide-treated, hypophysectomized, and intact rats. Further studies demonstrated binding in cultured bovine adrenocortical cells and in Y-1 cells, a cloned murine cell line of adrenal cortical origin. Scatchard analysis of specific binding data in cytosol from hypophysectomized rats revealed an apparent Kd of approximately 15 nM and a receptor content (Nmax) of 123 fmol/mg cytosol protein. Analysis of Y-1 cell cytosol showed a Kd of approximately 17 nM and Nmax of 190 fmol/mg protein. The binding site in hypophysectomized rats had the following steroid specificities: high affinity for dexamethasone, corticosterone, and progesterone; moderate affinity for 11 beta-cortisol, and low affinity for testosterone, estradiol, pregnenolone, and 11 alpha-cortisol. Sedimentation in sucrose density gradients revealed 8S binding peaks in cytosols prepared from intact rat adrenal glands, Y-1 cells, and cultured bovine adrenocortical cells. Time- and temperature-dependent nuclear uptake of [3H]dexamethasone in Y-1 cells was demonstrated. In vivo treatment of hypophysectomized rats with dexamethasone significantly enhanced the rate of adrenal atrophy. ACTH stimulation tests in hypophysectomized rats showed a decreased corticosterone response in dexamethasone-treated rats compared to that in control animals. However, in vitro, there was no evidence for an effect of dexamethasone on ACTH-stimulated corticosterone production. The data indicate that the adrenal cortex possesses a high affinity binding site that fulfills the criteria for a glucocorticoid receptor. Glucocorticoid administration enhances adrenal atrophy and impairs adrenal function. We speculate that this action contributes to the suppressive effect of glucocorticoids on the pituitary-adrenal axis.

Adrenal Cortex↗

Receptors for calcitonin gene-related peptide (CGRP) in the rat adrenal cortex.

We previously demonstrated the presence of adrenomedullin receptors in the rat adrenal cortex. There is evidence, however, that the actions of adrenomedullin may also be mediated by the CGRP receptor. The present study was designed to determine whether specific CGRP receptors are present in the rat adrenal cortex. Adrenal glands were, sectioned and immunostained with a primary antibody raised against the first intracellular loop of the CGRP-I receptor. Staining was visualised using alkaline phosphatase and vector red. Immunostaining for the CGRP-I receptor was found in the zona glomerulosa and the adrenal medulla, but not in the inner adrenocortical zones. ACTH treatment caused an increase in staining intensity in the glomerulosa. Ligand binding studies suggested the existence of two populations of CGRP binding sites, one with a Kd of 0.1 nM, the second of 37 nM. Only CGRP-I and adrenomedullin displaced labeled CGRP binding. These results suggest that the CGRP-I receptor is expressed in the adrenal zona glomerulosa and that a second class of binding site is also present. The CGRP-I receptor appears to be regulated by ACTH.

Adrenal Cortex↗

Three dimensional organization of mammalian adrenal cortex. A scanning electron microscopic study.

The adrenal cortex of different mammals was studied by SEM in order to demonstrate its actual three-dimensional organization. In the rat, as well as in the cat and pig, the adrenal cortex appeared as a "tunnelled continuum" of polyhedral cells arranged in plate-like structures (laminae). This laminar arrangement was more evident in the inner fasciculate and reticular zones where the cortex revealed a striking similarity to liver tissue. The polyhedral cells of all cortical zones possessed regular facets populated by small pits, larger invaginations and numerous microvilli with the exception of very short and smooth areas probably corresponding to attachment zones and/or gap junctions. This cellular architecture produced a labyrinthic system of intercellular channels or lacunae in which the capillaries were suspended. The pericapillary areas of this labyrinth contained microvilli, amorphous material, a delicate net of fibrils and occasional cells. The intercellular compartment of this lacunar system was mainly bordered by numerous microvilli arising from endocrine cells. The luminal surface of the capillary wall showed not only irregularly protruding margins (interpretable as endothelial junctions) but also clearly overlapping and flattened endothelial extensions. In all the animals and areas of the adrenal cortex examined, the endothelial wall was provided with abundant clusters of small fenestrations (about 50 nm in diameter) generally arranged in sieve plates. Larger fenestrations were noted mainly in the fasciculate and reticular zones of the cat and pig and occasionally in the rat. A final point related to the nature and significance of sinusoidal fenestrations was the occurrence of irregularly shaped and intracapillary located cells mainly noted in the deeper zones of the fasciculate and reticular zones of the gland. These elements--possessing the surface characteristics of macrophages--were observed, with their irregular and slender evaginations, in close proximity to the large fenestrations in a manner reminiscent of Kupffer cells within the lumen of liver sinusoids.

Adrenal Cortex↗

Production and metabolism of serotonin (5-HT) by the human adrenal cortex: paracrine stimulation of aldosterone secretion by 5-HT.

In the human adrenal cortex, serotonin (5-HT) is contained in mast-like cells, and we have shown that 5-HT stimulates aldosterone secretion, suggesting that 5-HT may control glomerulosa cells through a paracrine mechanism. Concurrently, the presence of 5-hydroxyindolacetic acid in human adrenocortical extracts indicates that 5-HT may be metabolized after local release by mast cells. The aim of the present study was to investigate in vitro the production and metabolism of 5-HT by the human adrenal cortex. Perifused adrenal slices released spontaneously detectable amounts of 5-HT (0.74 +/- 0.38 fmol/mg wet tissue.min). The mast cell-depleting drug compound 48/80 induced a burst of 5-HT secretion followed by a gradual increase in aldosterone production. Administration of the specific 5-HT(4) receptor antagonist GR 113808 (10(-6) M) did not affect compound 48/80-induced 5-HT release but abolished the stimulatory effect of compound 48/80 on aldosterone secretion, indicating that 5-HT released locally is responsible for a paracrine control of steroidogenesis. Incubation of cells from the human adrenal cortex with 5-HT (10(-5) M) provoked the formation of the 5-HT metabolite 5-hydroxytryptophol. The type A monoamine oxidase (MAO) inhibitor clorgyline (10(-6) M) suppressed the metabolism of 5-HT into 5-hydroxytryptophol. Immunocytochemical staining of cultured cells revealed the presence of a subpopulation of MAO-A-positive cells. Double labeling with an antiserum against chromogranin A showed that MAO-A was actually contained in chromaffin cells. Similarly, immunohistochemical staining of adrenal slices showed that MAO-A was expressed in chromaffin cells located both in the medulla and in intracortical rays. In conclusion, the present study shows that, in the human adrenal cortex, 5-HT, released by mast-cells, may stimulate aldosterone secretion in a paracrine manner. Our data also indicate that 5-HT is metabolized by MAO-A located in intracortical chromaffin cells.

Adrenal Cortex↗

Partial purification of a metalloprotease catalyzing the processing of adrenodoxin precursor in bovine adrenal cortex mitochondria.

In vitro translation of bovine adrenal cortex RNA in rabbit reticulocyte lysate cell-free system produced the precursor form of adrenodoxin having a molecular weight of approximately 22,000 daltons, which was about 10,000 daltons larger than mature adrenodoxin. The precursor of adrenodoxin was efficiently imported into adrenal cortex mitochondria in vitro. The precursor was also imported into rat liver mitochondria, suggesting the lack of tissue specificity and species specificity of the import process. The enzyme which processed the precursor of adrenodoxin to the mature form was in the matrix fraction from bovine adrenal cortex mitochondria, and the processing protease was partially purified from the matrix fraction. The apparent molecular weight of the processing protease was about 60,000 daltons as determined by Sephadex G-150 gel filtration, and its activity was optimal at pH 8.5. The processing protease was not inhibited by various bacterial protease inhibitors examined. Metal chelators (EGTA, GTP, 8-hydroxyquinoline, and Zincon) inhibited the processing, and EDTA and o-phenanthroline were more strongly inhibitory than other chelators. The processing protease was completely inactivated by incubation with 10 microM EDTA, and its activity was restored by addition of excess amounts of Mn2+, Fe2+, or Co2+. These results indicate that the maturation of the precursor of adrenodoxin is catalyzed by a soluble metalloprotease in the matrix.

Adrenal Cortex↗

Adrenal cortex transplantation after bilateral total adrenalectomy in the rat.

An experimental animal model with adrenal cortex transplantation was developed to study adrenal cortex replacement therapy in patients with multiple endocrine neoplasia type 2 who have had bilateral adrenalectomy for pheochromocytomas. Adrenal cortex of syngenetic rats was isolated from the medulla by collagenase digestion and a defined sedimentation. The cell suspension of the cortical cells was implanted under the kidney capsule of untreated syngenetic rats. After two weeks the recipients were bilaterally adrenalectomized. Serum corticosterone levels were measured as an estimate of function of the grafts. All recipients were healthy throughout the observation period, whereas all adrenalectomized controls died within 18 days. Vital cortex cells could be demonstrated in the explanted grafts by immunohistochemistry. Corticosterone levels of transplanted animals were nearly normal (9.5 ng/100 mL +/- 0.4) compared to the controls (0.20 ng/mL +/- 0.06). This animal model of adrenal cortex transplantation allows the separation of medullary from cortical cells. After transplantation, these cortical cells survived for eight weeks and were able to replace the adrenal cortex function.

Adrenal Cortex↗