A novel cell layer without corticosteroid-synthesizing enzymes in rat adrenal cortex: histochemical detection and possible physiological role.

Among the endocrine organs, the adrenal cortex appears to be the most vulnerable to chemically induced injury. A wide variety of chemicals has been found to cause morphological or functional lesions in the gland. Some of the lesions are highly localized to specific anatomical zones of the adrenal cortex, and the resulting functional deficits depend on the physiological role(s) of the zone affected. In addition, metabolic activation is an important factor contributing to the gland's vulnerability to chemical injury. For example, carbon tetrachloride (CCl4) causes adrenocortical necrosis, but only of the innermost zone of the gland, the zona reticularis. The apparent reason for the localized effect of CCl4 in the adrenal cortex is that only the cells of the zona reticularis have the enzymatic capacity to activate CCl4, resulting in lipid peroxidation and covalent binding to cellular macromolecules. By contrast, the mineralocorticoid antagonist, spironolactone, causes functional lesions in the adrenal cortex that are limited to the middle zone of the gland, the zona fasciculata. The explanation again involves metabolic activation; only the zona fasciculata converts spironolactone to a highly reactive metabolite that effects the destruction of several enzymes that are required for steroid hormone synthesis. These findings indicate that bioactivation plays a critical role in the mechanism(s) of action of various toxic agents on the adrenal cortex and also may be responsible for the anatomically localized effects of many chemicals.

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Physiological role of aldosterone in pregnancy, importance of correction in pathological conditions. What is known about pharmacological targets

Translational Medicine ◽

10.18705/2311-4495-2021-8-4-35-46 ◽

2021 ◽

Vol 8 (4) ◽

pp. 35-46

Author(s):

V. A. Karabeshkina ◽

V. V. Ishkaraeva ◽

I. E. Zazerskaya

Keyword(s):

Blood Pressure ◽

Adrenal Cortex ◽

Physiological Role ◽

Trophoblast Invasion ◽

Renin Angiotensin Aldosterone System ◽

Placental Perfusion ◽

Pathological Conditions ◽

Pharmacological Targets ◽

In Pregnancy

Aldosterone is the main mineralocorticosteroid hormone of the human adrenal cortex. It plays a key role in the regulation of kidney and cardiovascular function. Its role especially increases in the adaptation of the woman’s body during pregnancy, and consists in maintaining the balance of electrolytes, blood pressure, ensuring sufficient trophoblast invasion and adequate placental perfusion. This article describes the mechanism of synthesis and action of aldosterone, its biological role and place in the structure of the renin-angiotensin-aldosterone system (RAAS). A special place is given to aldosterone in maintaining hemodynamics during physiological pregnancy, and to violations of the RAAS, as a key to understanding the links in the pathogenesis of preeclampsia.

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Effects and fate of human IGF-binding protein-5 in rat osteoblast cultures

AJP Endocrinology and Metabolism ◽

10.1152/ajpendo.1996.271.6.e1029 ◽

1996 ◽

Vol 271 (6) ◽

pp. E1029-E1035 ◽

Cited By ~ 1

Author(s):

C. Schmid ◽

I. Schlapfer ◽

M. A. Gosteli-Peter ◽

E. R. Froesch ◽

J. Zapf

Keyword(s):

Cell Layer ◽

Physiological Role ◽

Igf Binding Proteins ◽

Igf Binding ◽

Rat Osteoblast ◽

Igf Binding Protein ◽

Rat Osteoblasts ◽

Igfbp 3 ◽

Insulin Like Growth Factors

Osteoblasts prepared from calvaria of newborn rats produce insulin-like growth factors (IGF) and IGF-binding proteins (IGFBP), IGFBP-5 was discovered in bone extracts. However, we could not detect IGFBP-5 in the medium of newborn rat osteoblasts, although we found mRNA expression. To find an explanation for this discrepancy and to learn more about the physiological role of IGFBP-5 in these cells, we studied the biological activity and the fate of recombinant human (rh) IGFBP-5 in comparison to rhIGFBP-3. IGFBP-5 but not IGFBP-3 stimulated thymidine incorporation into DNA both in the absence and presence of IGF-I. However, IGFBP-5 did not enhance uridine incorporation into RNA and glucose incorporation into glycogen. 125I-rhIGFBP-5 but not 125I-rhIGFBP-3 rapidly disappeared from the culture medium consistent with the observation that endogenous (rat) IGFBP-3 but not IGFBP-5 accumulated in the medium. However, intact 125I-labeled or unlabeled rhIGFBP-5 was associated with the cell-layer matrix, whereas IGFBP-5 fragments appeared in the medium. Trapping of IGFBP-5 in the cell layer matrix may enhance local availability of IGF.

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Expression of activin/inhibin signaling components in the human adrenal gland and the effects of activins and inhibins on adrenocortical steroidogenesis and apoptosis

Journal of Endocrinology ◽

10.1677/joe.0.1780479 ◽

2003 ◽

Vol 178 (3) ◽

pp. 479-489 ◽

Cited By ~ 43

Author(s):

T Vanttinen ◽

J Liu ◽

T Kuulasmaa ◽

P Kivinen ◽

R Voutilainen

Keyword(s):

Adrenal Gland ◽

Adrenal Cortex ◽

Apoptotic Cell ◽

Regulatory Protein ◽

Physiological Role ◽

Activin A ◽

Terminal Deoxynucleotidyl Transferase ◽

Zona Fasciculata ◽

Zona Reticularis ◽

Signaling Components

Activins and inhibins are structurally related glycoprotein hormones modulating pituitary FSH secretion and gonadal steroidogenesis. Activins and inhibins are also produced in the adrenal cortex where their physiological role is poorly known. Hormonally active human adrenocortical tumors express and secrete inhibins, while in mice adrenal inhibins may function as tumor suppressors. To clarify the significance of adrenal activins and inhibins we investigated the localization of activin/inhibin signaling components in the adrenal gland, and the effects of activins and inhibins on adrenocortical steroidogenesis and apoptosis.Activin receptor type II/IIB and IB, activin signal transduction proteins Smad2/3, and inhibin receptor betaglycan were expressed throughout the adrenal cortex, whereas Smad4 expression was seen mainly in the zona reticularis and the innermost zona fasciculata as evaluated by immunohistochemistry. Treatment of cultured adrenocortical carcinoma NCI-H295R cells with activin A inhibited steroidogenic acute regulatory protein and 17alpha-hydroxylase/17,20-lyase mRNA accumulation as evaluated by the Northern blot technique, and decreased cortisol, androstenedione, dehydroepiandrosterone and dehydroepiandrosterone sulfate secretion as determined by specific enzyme immunoassays. Activin A increased apoptosis as measured by a terminal deoxynucleotidyl transferase in situ apoptosis detection method. Inhibins had no effect on steroidogenesis or apoptosis.In summary, activin/inhibin signaling components are coexpressed in the zona reticularis and the innermost zona fasciculata indicating full signaling potential for adrenal activins and inhibins in these layers. Activin inhibits steroidogenic enzyme gene expression and steroid secretion, and increases apoptosis in human adrenocortical cells. Thus, the activin-inhibin system may have a significant role in the regulation of glucocorticoid and androgen production and apoptotic cell death in the human adrenal cortex.

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SEM of Hepatocytes and Biliary Passages in Goldfish Liver

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100080213 ◽

1977 ◽

Vol 35 ◽

pp. 556-557

Author(s):

Waykin Nopanitaya ◽

Joe W. Grisham ◽

Johnny L. Carson

Keyword(s):

Carassius Auratus ◽

Cell Layer ◽

Three Dimensional ◽

Cell Types ◽

Biliary System ◽

Fish Food ◽

Commercial Fish ◽

Goldfish Carassius Auratus ◽

Commercial Fish Food

An interesting feature of the goldfish liver is the morphology of the hepatic plate, which is always formed by a two-cell layer of hepatocytes. Hepatic plates of the goldfish liver contain an infrequently seen second type of cell, in the centers of plates between two hepatocytes. A TEH study by Yamamoto (1) demonstrated ultrastructural differences between hepatocytes and centrally located cells in hepatic plates; the latter were classified as ductule cells of the biliary system. None of the previous studies clearly showed a three-dimensional organization of the two cell types described. In the present investigation we utilize SEM to elucidate the arrangement of hepatocytes and bile ductular cells in intralobular plates of goldfish liver.Livers from young goldfish (Carassius auratus), about 6-10 cm, fed commercial fish food were used for this study. Hepatic samples were fixed in 4% buffered paraformaldehyde, cut into pieces, fractured, osmicated, CPD, mounted Au-Pd coated, and viewed by SEM at 17-20 kV. Our observations were confined to the ultrastructure of biliary passages within intralobular plates, ductule cells, and hepatocytes.

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Anchoring Fibrils in Arterial Endothelium

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100063287 ◽

1969 ◽

Vol 27 ◽

pp. 274-275

Author(s):

A. Trillo

Keyword(s):

Carotid Arteries ◽

Animal Species ◽

Cell Layer ◽

Present Communication ◽

Internal Elastic Lamina ◽

Endothelial Cell Layer ◽

Structural Details ◽

Rats And Mice ◽

Arterial Endothelium ◽

Elastic Lamina

There are conflicting reports regarding some fine structural details of arteries from several animal species. Buck denied the existence of a sub-endothelial space, while Karrer and Keech described a space of variable width which separates the endothelium from the underlying internal elastic lamina in aortas of aging rats and mice respectively.The present communication deals with the ultrastrueture of the interface between the endothelial cell layer and the internal elastic lamina as observed in carotid arteries from rabbits of varying ages.

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Ultrastructural Cytopiasmic Changes of Adrenal Cortex During Pregnancy

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100063408 ◽

1969 ◽

Vol 27 ◽

pp. 298-299

Author(s):

T. M. Murad ◽

Karen Israel ◽

Jack C. Geer

Keyword(s):

Adrenal Gland ◽

Steroid Hormones ◽

Adrenal Cortex ◽

Lipid Droplets ◽

Plasma Cholesterol ◽

Adrenal Steroids ◽

Dynamic Changes ◽

Cortical Cells ◽

Acetyl Coenzyme A ◽

Adrenal Cortical Cells

Adrenal steroids are normally synthesized from acetyl coenzyme A via cholesterol. Cholesterol is also shown to enter the adrenal gland and to be localized in the lipid droplets of the adrenal cortical cells. Both pregnenolone and progesterone act as intermediates in the conversion of cholesterol into steroid hormones. During pregnancy an increased level of plasma cholesterol is known to be associated with an increase of the adrenal corticoid and progesterone. The present study is designed to demonstrate whether the adrenal cortical cells show any dynamic changes during pregnancy.

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Adrenocortical Ultrastructure in Ectopic Acth Syndrome

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100091172 ◽

1976 ◽

Vol 34 ◽

pp. 238-239

Author(s):

K. Kovacs ◽

E. Horvath ◽

W. Singer

Keyword(s):

Adrenal Cortex ◽

Zona Glomerulosa ◽

Ectopic Acth Syndrome ◽

Pituitary Neoplasms ◽

Electron Microscopic ◽

Adrenocortical Cells ◽

Cell Hyperplasia ◽

Ectopic Acth ◽

Ectopic Acth Production ◽

Microscopic Findings

Secretion of ACTH by non-pituitary neoplasms is recognized with increasing frequency. While the clinical and biochemical changes associated with ectopic ACTH production have been extensively studied recently, relatively little attention was focused on the morphology of the adrenal cortex and, to our knowledge, the fine structure of the adrenocortical cells in cases of ectopic ACTH syndrome has not been described so far. We report here the electron microscopic findings in the adrenal cortex of a 50-year-old man with a pancreatic apudoma. The patient showed the characteristic clinical and biochemical features of ectopic ACTH syndrome and because of extensive hypercorticism, underwent bilateral adrenalectomy.By light microscopy, the adrenal cortices showed extensive compact cell hyperplasia and lipid depletion. The zona glomerulosa was present in small foci and, except for a few places, fasciculata cells were noted under the fibrous capsule.

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