Zona Fasciculata Cells Research Articles

CORRIGENDUM FOR "Dynamics of ACTH-Mediated Regulation of Gene Transcription in ATC1 and ATC7 Adrenal Zona Fasciculata Cell Lines".

CORRIGENDUM FOR "Dynamics of ACTH-Mediated Regulation of Gene Transcription in ATC1 and ATC7 Adrenal Zona Fasciculata Cell Lines".

Dynamics of ACTH-Mediated Regulation of Gene Transcription in ATC1 and ATC7 Adrenal Zona Fasciculata Cell Lines.

We tested the hypothesis that mouse ATC1 and ATC7 cells, the first adrenocortical cell lines to exhibit a complete zona fasciculata (ZF) cell phenotype, respond to dynamic ACTH stimulation in a similar manner as the adrenal gland in vivo. Exploiting our previous in vivo observations that gene transcription within the steroidogenic pathway is dynamically regulated in response to a pulse of ACTH, we exposed ATC1 and ATC7 cells to various patterns of ACTH, including pulsatile and constant, and measured the transcriptional activation of this pathway. We show that pulses of ACTH administered to ATC7 cells can reliably stimulate a pulsatile pattern of transcriptional activity that is comparable to that observed in adrenal ZF cells in vivo. Hourly pulses of ACTH stimulate dynamic increases in CREB phosphorylation (pCREB) and transcription of genes involved in critical steps of steroidogenesis including signal transduction (e.g., MRAP), cholesterol delivery (e.g., StAR), and steroid biosynthesis (e.g., CYP11A1), as well as those relating to transcriptional regulation of steroidogenic factors (e.g., SF-1 and Nur-77). In contrast, constant ACTH stimulation results in a prolonged and exaggerated pCREB and steroidogenic gene transcriptional response. We also show that when a large dose of ACTH (100 nM) is applied after these treatment regimens, a significant increase in steroidogenic transcriptional responsiveness is achieved only in cells that have been exposed to pulsatile, rather than constant, ACTH. Our data support our in vivo observations that pulsatile ACTH is important for the optimal transcriptional responsiveness of the adrenal. Importantly, our data suggest that ATC7 cells respond to dynamic ACTH stimulation.

The possible structural changes in the adrenal gland cortex after induction of hepatic ischemia-reperfusion injury in male albino rats: Light and electron microscopic study.

The adrenal gland is an important endocrine gland in the body that secrets the adrenal hormones. One of the important clinical issues is the hepatic ischemia-reperfusion (IR) injury. Liver IR injury results in many distant organs dysfunctions such as lung, kidney, intestine, pancreas, and myocardium. The aim of the present study was to investigate the possible remote effects of hepatic IR on the structure of the adrenal cortex. Twenty healthy males, Sprague-Dawley albino rats aged 6-8 weeks were randomly divided into two groups (10 rats each): the sham control group (SC-group) and the ischemia-reperfusion group (IR-group). Sera were estimated for the following: aspartate transaminase (AST), alanine transaminase (ALT), lactic dehydrogenase (LDH), and corticosterone levels. Also oxidative markers such as malondialdehyde (MDA) and tumor necrosis factor-α (TNF-α), and the antioxidative enzyme, catalase were measured. Adrenal glands were processed for light and transmission electron microscopic study. The results showed a significant increase in serum liver enzymes (AST, ALT, and LDH), corticosterone, MDA, and TNF-α levels and a significant decrease in serum levels of catalase in IR-group compared with SC-group. Adrenal cortical tissue of IR-group showed the loss of normal appearance. Some cells of zona glomerulosa and most of the zona fasciculata cells appeared swollen and degenerated with highly vacuolated cytoplasm. Other cells were shrunken with deeply acidophilic cytoplasm and pyknotic nuclei. Degenerated mitochondria with disrupted cristae, lipid droplets were confluent and dilated smooth endoplasmic reticulum were seen. Few zona reticularis cells had the dark nucleus and cytoplasmic vacuolations. In the different zones, blood capillaries were markedly congested and some inflammatory cells infiltrations were observed. Liver IR affected the structure of the adrenal cortex.

Exposure to cell phone radiofrequency changes corticotrophin hormone levels and histology of the brain and adrenal glands in male Wistar rat.

Objective(s):Nowadays, the electromagnetic field-emitting devices are used routinely in our lives. Controversial reports exist concerning the effects of mobile radiofrequency (RF) on different parts of the body, especially stress hormones. The main goal of the present work was to study the long-term effects of mobile RF900 MHz exposure with special focus on the adrenal gland pathophysiology and function. Materials and Methods:Adult male Wistar rats were exposed to mobile RF 6 hr daily for 4–8 weeks. Intact and switched-off exposed animals were considered as controls. Plasma ACTH and cortisol levels were measured by the ELISA method. At the end of the experiment, a histological study was done on adrenal gland and brain tissues by hematoxylin and eosin staining. The thickness of the fasciculate layer of the adrenal gland, and its cell count and perimeter were measured using the Fiji software. Results:Enhanced plasma ACTH and cortisol levels were found after prolonged exposure to mobile RF. The fasciculata layer of adrenal cortex eventually thickened following mobile RF radiation. While the number of cells in zona fasciculata remained constant, the cell size and perimeter increased during RF exposure. Finally, we found that vacuolization in brain tissue and the number and size of vacuoles considerably increased during two months of RF exposure. Conclusion:Cell phone RF exposure induced significant hormonal and structural changes in adrenal gland and brain tissues. Therefore, the public should be aware and limit their exposure as much as possible.

Changes in Secretory Activity of Adrenal Zona Fasciculata Cells in Pubertal Rats Exposed to Low Doses of DDT in Different Periods of Ontogeny.

We studied secretory activity of adrenal zona fasciculata cells in pubertal rats exposed to low doses of endocrine disrupter DDT during prenatal and postnatal periods and only during postnatal period. In exposed animals, circulatory disturbances leading to degeneration and necrosis of cells as well as regeneration foci were revealed in the outer zona fasciculata. In rats exposed to DDT during the prenatal and postnatal periods, compensatory increase in secretory activity of cells due to increase in mitochondria content was noted in the inner zona fasciculata, which determined elevated serum concentration of corticosterone. In rats exposed to DDT only during the postnatal development, functional activity of zona fasciculata cells was suppressed, which attested to delayed upregulation of secretion.

Ectopic adrenal tissue of spermatic cord in a 3- year- old boy, an incidental finding during orchidopexy: A case report

Ectopic adrenal tissue is usually found in kidney and retroperitoneum, yet other locations are considered uncommon. Spermatic cord remains one of the sites where this entity is mostly incidentally found during surgical procedure in childhood. Macroscopically, it represents as yellowish, lipomatous nodule. We present a case of ectopic adrenal tissue of spermatic cord in a 3- year- old boy, found during orchidopexy of the right testicle. Histopathological analysis of the spermatic cord nodule revealed adrenal cortical tissue composed of zona fasciculata cells. Although usually being benign and asymptomatic, cases of hyperplasia, adenoma and carcinoma arising from ectopic adrenal tissue have been reported. Therefore, removal of this tissue, when detected, is recommended.

Aldosterone-Producing Adenomas: Histopathology-Genotype Correlation and Identification of a Novel CACNA1D Mutation.

Mutations in KCNJ5, ATP1A1, ATP2B3, CACNA1D, and CTNNB1 are thought to cause the excessive autonomous aldosterone secretion of aldosterone-producing adenomas (APAs). The histopathology of KCNJ5 mutant APAs, the most common and largest, has been thoroughly investigated and shown to have a zona fasciculata-like composition. This study aims to characterize the histopathologic spectrum of the other genotypes and document the proliferation rate of the different sized APAs. Adrenals from 39 primary aldosteronism patients were immunohistochemically stained for CYP11B2 to confirm diagnosis of an APA. Twenty-eight adenomas had sufficient material for further analysis and were target sequenced at hot spots in the 5 causal genes. Ten adenomas had a KCNJ5 mutation (35.7%), 7 adenomas had an ATP1A1 mutation (25%), and 4 adenomas had a CACNA1D mutation (14.3%). One novel mutation in exon 28 of CACNA1D (V1153G) was identified. The mutation caused a hyperpolarizing shift of the voltage-dependent activation and inactivation and slowed the channel's inactivation kinetics. Immunohistochemical stainings of CYP17A1 as a zona fasciculata cell marker and Ki67 as a proliferation marker were used. KCNJ5 mutant adenomas showed a strong expression of CYP17A1, whereas ATP1A1/CACNA1D mutant adenomas had a predominantly negative expression (P value =1.20×10-4). ATP1A1/CACNA1D mutant adenomas had twice the nuclei with intense staining of Ki67 than KCNJ5 mutant adenomas (0.7% [0.5%-1.9%] versus 0.4% [0.3%-0.7%]; P value =0.04). Further, 3 adenomas with either an ATP1A1 mutation or a CACNA1D mutation had >30% nuclei with moderate Ki67 staining. In summary, similar to KCNJ5 mutant APAs, ATP1A1 and CACNA1D mutant adenomas have a seemingly specific histopathologic phenotype.

Age-dependent effects of Armc5 haploinsufficiency on adrenocortical function.

Inactivating mutations in the Armadillo repeat-containing 5 (ARMC5) gene have recently been discovered in primary macronodular adrenal hyperplasia (PMAH), a cause of Cushing syndrome. Biallelic ARMC5 inactivation in PMAH suggested that ARMC5 may have tumor suppressor functions in the adrenal cortex. We generated and characterized a new mouse model of Armc5 deficiency. Almost all Armc5 knockout mice died during early embryonic development, around 6.5 and 8.5 days. Knockout embryos did not undergo gastrulation, as demonstrated by the absence of mesoderm development at E7.5. Armc5 heterozygote mice (Armc5+/-) developed normally but at the age of 1 year, their corticosterone levels decreased; this was associated with a decrease of protein kinase A (PKA) catalytic subunit α (Cα) expression both at the RNA and protein levels that were also seen in human patients with PMAH and ARMC5 defects. However, this was transient, as corticosterone levels normalized later, followed by the development of hypercorticosteronemia in one-third of the mice at 18 months of age, which was associated with increases in PKA and Cα expression. Adrenocortical tissue analysis from Armc5+/- mice at 18 months showed an abnormal activation of the Wnt/β-catenin signaling pathway in a subset of zona fasciculata cells. These data confirm that Armc5 plays an important role in early mouse embryonic development. Our new mouse line can be used to study tissue-specific effects of Armc5. Finally, Armc5 haploinsufficiency leads to Cushing syndrome in mice, but only later in life, and this involves PKA, its catalytic subunit Cα, and the Wnt/β-catenin pathway.

Comparative Study on The Safety of Aspartame and Stevia on The Adrenal-Pituitary Axis of Adult Male Albino Rats: Histological and Immunohistochemical Study

Introduction: Aspartame is the most widely used artificial sweeteners. Stevia is a worldwide natural sweetener plant with medicinal and commercial importance. Stress responses are mediated both in the central and peripheral nervous system. The principal effectors of the stress response are localized in the hypothalamus, the anterior lobe of the pituitary gland, and the adrenal gland. This is commonly referred to as the hypothalamic-pituitary-adrenal axis.Aim: To compare the effect of aspartame and stivea on the pituitary adrenal axis.Material and Methods: A total of 30 adult male albino rats were equally divided into three groups. Group I was the Control Group. Group II (ASP Group) received aspartame (ASP), at daily oral dose 250 mg/kg for 4 weeks. .Group III (stevia Group) received stevia at daily oral dose 250 mg/kg for 4 weeks.Results: : In aspartame-treated group there was apoptosis of zona fasciculata cells with subsequent corticotrophic hyperplasia. In stevia treated groups minimal changes were observed with no significant changes in number of corticotrophes.Conclusion: As a natural sweetener, stevia is safer than aspartame on the adrenal pituitary axis.

Light and electron microscopic study on the effect of immobilization stress on adrenal cortex of adult rats and possible ameliorative role of vitamin E.

Background: Modern society is full of stress. Immobilization stress is a model used in animals to study its effects. Vitamin E is an antioxidant that protects biological membranes from oxidative stress. Objectives: This study aimed to investigate the effects of immobilization stress on the adrenal cortex of rats and the ameliorative effect of vitamin E.Materials and Methods: Forty adult male rats were used in this study and were divided equally into 4 groups. Group I:were divided equally into negative and positive controls. Group II: rats received vitamin E at a dose of 40 I.U/kg by gastric tube for 30 days. Group III: rats subjected to immobilization stress 2 hours /day for 30 days. Group IV: rats subjected to immobilization stress 2 hours /day and received 40 I.U/kg of vitamin E for 30 days. Adrenal sections were histologically prepared and examined. Results: Group II was comparable to group IA. Group III revealed zona glomerulosa (ZG) with loss of normal architecture, zona fasciculata (ZF) with multiple cells containing cytoplasmic vacuolations and darkly stained nuclei. By EM ZG cells appeared with accumulations of lipid droplets and lysosomes, irregular nuclear envelopes and chromatin condensation. ZF cells showed numerous lipid droplets and irregular nuclear envelopes. There were significant increases in the mean area of collagen fibers and mean serum cortisol level. Group IV revealed regression of these changes and increase in the mean count of CD44 +ve cells.Conclusions: Immobilization stress exerted deleterious suprarenal cortical changes and vitamin E had an ameliorative effect.

Aminoglutethimide-induced lysosomal changes in adrenal gland in mice

Aminoglutethimide is a steroidogenesis inhibitor and inhibits a cholesterol side-chain cleavage enzyme (CYP11A1) that converts cholesterol to pregnenolone in mitochondria. We investigated histopathological changes induced by 5-day administration of AG in mice. Cytoplasmic vacuoles of various sizes and single cell necrosis were found in zona fasciculata cells in AG-treated mice. Some vacuoles were positive for adipophilin, whereas others were positive for lysosome-associated membrane protein-2 on immunohistochemical staining, indicating they were enlarged lipid droplets and lysosomes, respectively. Electron microscopy revealed enlarged lysosomes containing damaged mitochondria and lamellar bodies in zona fasciculata cells, and they were considered to reflect the intracellular protein degradation processes, mitophagy and lipophagy. From these results, we showed that AG induces excessive lipid accumulation and mitochondrial damage in zona fasciculata cells, which leads to an accelerated lysosomal degradation in mice.

Effect of monosodium glutamate on body weight and the histological structure of the zona fasciculata of the adrenal cortex in young male albino rats

Introduction Monosodium glutamate (MSG) is commonly used as a flavor enhancer in both home and restaurant cooking. Aim The aim of this work was to clarify the possible effect of MSG administration on the body weight and the histological structure of the zona fasciculata (ZF) of the adrenal cortex in young male albino rats and to assess whether or not this effect was reversible. Materials and methods A total of 40 male albino rats aged 4 weeks were weighed at the onset of the study and then divided into two equal groups. The control rats (group I) were held without medication either for 2 weeks (group Ia) or for 4 weeks (group Ib) and then killed. The experimental rats (group II) received a daily oral dose of MSG (4 mg/g body weight) dissolved in 3 ml of distilled water for 2 weeks and then 10 of them were killed 2 h after the last dose (group IIa); the other 10 rats were held without medication for another 2 weeks and then killed (group IIb). All rats were weighed before scarification. Sections of the adrenal glands were examined with light and electron microscopes. Thickness of the ZF was measured in all subgroups. Data of the final body weight and ZF thickness were analyzed as mean±SD and P values were calculated. Results Statistically, the final body weight of rats increased in both groups IIa and IIb and also the thickness of the ZF increased in group IIa as compared with their controls. Histologically, group IIa showed loss of the cord-like architecture of ZF cells. They appeared distended with highly vacuolated cytoplasm that was ultrastructurally full of lipid droplets. Group IIb revealed partial improvement and retained normal thickness and structure of the ZF. Conclusion MSG causes histopathological changes in the ZF of the adrenal cortex, increasing its thickness and its secretion, and this could explain the increased final body weight. These changes are reversible but may need a long time to regain their normal values.

Histological effect of nicotine on adrenal zona fasciculata and the effect of grape seed extract with or without withdrawal of nicotine

Cigarette smoking is harmful to the health of both smokers and nonsmokers. It is a major cause of death. This study aimed to investigate the structural changes in the zona fasciculata of albino rats caused by nicotine and the protective effect of grape seeds with or without the stoppage of nicotine administration. Thirty-five adult male rats were used and equally divided into five groups: negative and positive control groups (Groups I and II), nicotine-treated group (Group III), nicotine- and grape seed extract-treated group (Group IV), and nicotine withdrawal and grape seed extract-treated group (Group V). Adrenal glands were dissected and prepared for histological studies. The majority of zona fasciculata cells of Group III showed striking changes in terms of swelling of the cells with marked cytoplasmic vacuolation, many pyknotic nuclei, and increased immunoexpression to caspase 3 antibodies. By electron microscopy, a marked increase in lipid deposition with its appearance in the capillary between zona fasciculata cells was noticed. Heterochromatic nuclei and dilated smooth endoplasmic reticulum were noted. Degenerated mitochondria and some mitochondria that had cavitation with a progressive loss of their cristae were seen. The zona fasciculata cells of Group IV were partially improved, while in Group V, those cells showed complete improvement. We can conclude that nicotine causes severe histological changes in zona fasciculata cells. Grape seed extract can partially ameliorate these changes, and complete recovery is achieved with grape seed extract after the stoppage of nicotine administration.

Chromatin Fractal Organization, Textural Patterns, and Circularity of Nuclear Envelope in Adrenal Zona Fasciculata Cells.

Despite previous research efforts in the fields of histology and cell physiology, the relationship between chromatin structural organization and nuclear shape remains unclear. The aim of this research was to test the existence and strength of correlations between mathematical parameters of chromatin microarchitecture and roundness of the nuclear envelope. On a sample of 240 nuclei of adrenal zona fasciculata cells stained using the DNA-specific Feulgen method, we quantified fractal parameters such as fractal dimension and lacunarity, as well as textural parameters such as angular second moment (ASM), entropy, inverse difference moment, contrast, and variance. Circularity of the nuclear envelope was determined from the nuclear area and perimeter. The results indicate that there is a statistically significant negative correlation between chromatin ASM and circularity. Moreover, there was a statistically significant positive correlation between chromatin fractal dimension and envelope circularity. This is the first study to demonstrate these relationships in adrenal tissue, and also one of the first studies to test the connection between circularity and fractal and gray-level co-occurrence matrix parameters in DNA-specific Feulgen stain. The results could be useful both as an addition to the current knowledge on chromatin/nuclear envelope interactions, and for design of future computer-assisted research software for evaluation of nuclear morphology.

ACTH Modulates PTP-PEST Activity and Promotes Its Interaction With Paxillin.

Adrenocorticotropic hormone (ACTH) treatment has been proven to promote paxillin dephosphorylation and increase soluble protein tyrosine phosphatase (PTP) activity in rat adrenal zona fasciculata (ZF). Also, in-gel PTP assays have shown the activation of a 115-kDa PTP (PTP115) by ACTH. In this context, the current work presents evidence that PTP115 is PTP-PEST, a PTP that recognizes paxillin as substrate. PTP115 was partially purified from rat adrenal ZF and PTP-PEST was detected through Western blot in bioactive samples taken in each purification step. Immunohistochemical and RT-PCR studies revealed PTP-PEST expression in rat ZF and Y1 adrenocortical cells. Moreover, a PTP-PEST siRNA decreased the expression of this phosphatase. PKA phosphorylation of purified PTP115 isolated from non-ACTH-treated rats increased KM and VM . Finally, in-gel PTP assays of immunoprecipitated paxillin from control and ACTH-treated rats suggested a hormone-mediated increase in paxillin-PTP115 interaction, while PTP-PEST and paxillin co-localize in Y1 cells. Taken together, these data demonstrate PTP-PEST expression in adrenal ZF and its regulation by ACTH/PKA and also suggest an ACTH-induced PTP-PEST-paxillin interaction. J. Cell. Biochem. 117: 2170-2181, 2016. © 2016 The Authors. Journal of Cellular Biochemistry Published by Wiley Periodicals, Inc.

Sex-related gene expression profiles in the adrenal cortex in the mature rat: microarray analysis with emphasis on genes involved in steroidogenesis.

Notable sex-related differences exist in mammalian adrenal cortex structure and function. In adult rats, the adrenal weight and the average volume of zona fasciculata cells of females are larger and secrete greater amounts of corticosterone than those of males. The molecular bases of these sex-related differences are poorly understood. In this study, to explore the molecular background of these differences, we defined zone- and sex-specific transcripts in adult male and female (estrous cycle phase) rats. Twelve-week-old rats of both genders were used and samples were taken from the zona glomerulosa (ZG) and zona fasciculata/reticularis (ZF/R) zones. Transcriptome identification was carried out using the Affymetrix® Rat Gene 1.1 ST Array. The microarray data were compared by fold change with significance according to moderated t-statistics. Subsequently, we performed functional annotation clustering using the Gene Ontology (GO) and Database for Annotation, Visualization and Integrated Discovery (DAVID). In the first step, we explored differentially expressed transcripts in the adrenal ZG and ZF/R. The number of differentially expressed transcripts was notably higher in the female than in the male rats (702 vs. 571). The differentially expressed genes which were significantly enriched included genes involved in steroid hormone metabolism, and their expression levels in the ZF/R of adult female rats were significantly higher compared with those in the male rats. In the female ZF/R, when compared with that of the males, prevailing numbers of genes linked to cell fraction, oxidation/reduction processes, response to nutrients and to extracellular stimuli or steroid hormone stimuli were downregulated. The microarray data for key genes involved directly in steroidogenesis were confirmed by qPCR. Thus, when compared with that of the males, in the female ZF/R, higher expression levels of genes involved directly in steroid hormone synthesis were accompanied by lower expression levels of genes regulating basal cell functions.

Acaricide treatment prevents adrenocortical hyperplasia as a long-term stress reaction to psoroptic mange in cattle

In cattle, infestation with Psoroptes ovis mites may cause severe dermatitis (psoroptic mange) which compromises the health and welfare of the animals and may lead to significant economic losses. To investigate yet undocumented effects of psoroptic mange mite infestations and how successful therapy promotes animal health, the present study examined alterations of the skin, lymph nodes and adrenal glands of P. ovis infested Fleckvieh (Simmental) bulls treated with either ivermectin long-acting injection (IVM LAI; IVOMEC® GOLD, Merial; 3.15% ivermectin w/v) or saline (n=16 each). Approximately 8 weeks subsequent to experimental infestation with P. ovis, the bulls had developed mange and were administered either IVM LAI or saline once at 1mL/50kg body weight by subcutaneous injection. Mite counts were conducted in weekly intervals for determination of efficacy of treatment, and following humane euthanasia of the animals 8 weeks after treatment, skin samples from affected (mangy or previously mangy) and unaffected areas, prescapular lymph nodes and adrenal glands were collected for gross and pathohistological examination. In addition, four age-matching, uninfested Simmental bulls were sampled as controls for comparison.No P. ovis mites were detected on any IVM LAI-treated bull after 28 days following treatment whereas saline-treated bulls maintained infestation throughout the study. At sampling (approximately 16 weeks after experimental infestation and 8 weeks following saline or IVM LAI treatment), saline-treated bulls displayed a severe, exsudative dermatitis with significantly increased skin thickness and inflammatory cell infiltration, significantly enlarged, hyperplastic prescapular lymph nodes, as well as significantly increased adrenal gland weights and volumes as compared to P. ovis-infested, IVM LAI-treated bulls and uninfested controls. Quantitative stereological analysis revealed that the adrenal gland enlargement in P. ovis-infested, saline-treated bulls was due to a selective increase of the volume of the zona fasciculata in the adrenal cortex. Compared to uninfested controls and P. ovis-infested, IVM LAI-treated bulls, the number of epithelial cells in the zona fasciculata was significantly increased in P. ovis-infested, saline-treated bulls, while the zona fasciculata cell volumes did not differ between the three groups of cattle. While the single point determination of serum cortisol concentrations did not reveal significant differences between the three groups of cattle at tissue sampling, the hyperplastic growth of the adrenal cortex in the P. ovis-infested, saline-treated bulls provides morphologic evidence that a chronic stress reaction is one consequence of mange mite infestations that can be prevented by efficacious acaricidal treatment.

Toxicological profile of ultrapure 2,2',3,4,4',5,5'-heptachlorbiphenyl (PCB 180) in adult rats.

PCB 180 is a persistent non-dioxin-like polychlorinated biphenyl (NDL-PCB) abundantly present in food and the environment. Risk characterization of NDL-PCBs is confounded by the presence of highly potent dioxin-like impurities. We used ultrapure PCB 180 to characterize its toxicity profile in a 28-day repeat dose toxicity study in young adult rats extended to cover endocrine and behavioral effects. Using a loading dose/maintenance dose regimen, groups of 5 males and 5 females were given total doses of 0, 3, 10, 30, 100, 300, 1000 or 1700 mg PCB 180/kg body weight by gavage. Dose-responses were analyzed using benchmark dose modeling based on dose and adipose tissue PCB concentrations. Body weight gain was retarded at 1700 mg/kg during loading dosing, but recovered thereafter. The most sensitive endpoint of toxicity that was used for risk characterization was altered open field behavior in females; i.e. increased activity and distance moved in the inner zone of an open field suggesting altered emotional responses to unfamiliar environment and impaired behavioral inhibition. Other dose-dependent changes included decreased serum thyroid hormones with associated histopathological changes, altered tissue retinoid levels, decreased hematocrit and hemoglobin, decreased follicle stimulating hormone and luteinizing hormone levels in males and increased expression of DNA damage markers in liver of females. Dose-dependent hypertrophy of zona fasciculata cells was observed in adrenals suggesting activation of cortex. There were gender differences in sensitivity and toxicity profiles were partly different in males and females. PCB 180 adipose tissue concentrations were clearly above the general human population levels, but close to the levels in highly exposed populations. The results demonstrate a distinct toxicological profile of PCB 180 with lack of dioxin-like properties required for assignment of WHO toxic equivalency factor. However, PCB 180 shares several toxicological targets with dioxin-like compounds emphasizing the potential for interactions.

Channels and Pumps in Aldosterone-Producing Adenomas

Primary aldosteronism is the most common cause of secondary hypertension, with a prevalence of about 5% of the general hypertensive population and 10% of patients referred to hypertension specialty clinics. Aldosterone-producing adenomas (APAs) account for approximately 30–50% of cases of primary aldosteronism, and idiopathic hyperaldosteronism accounts for most of the rest of the cases. Aldosterone synthesis is regulated primarily by the renin-angiotensin system, potassium, ACTH, and to a lesser degree other peptides (1). Isolated adrenal zona glomerulosa and fasciculata cells from different species maintain a negative membrane resting potential determined by regulating membrane permeability to potassium (2, 3). Zona glomerulosa cells with hyperpolarized resting membrane voltages are steroidogenically inactive (4). Stimulation with angiotensin II, ACTH, or potassium results in membrane depolarization, opening of plasma membrane calcium channels, and mobilization of intracellular calcium, which increases activation of the calcium-calmodulin pathway, ultimately resulting in an increase in steroid biosynthesis and secretion (1). Several potassium channels have been described in rodent, bovine, and human adrenal cells, including inward rectifying and leak potassium currents that provide background potassium currents (reviewed in Ref. 3).

English

The Indian wild caught bat, Taphozous kachhensis at Ambai Nimbai (Maharashtra) shows continuous asynchronous breeding, exhibiting a seasonal polyoestry. The adrenal gland of T. kachhensis is made up of adrenocortical and chromaffin tissues. The adrenocortical tissue is comprised of two main types of cells, the steroid cells with abundance of lipid inclusions and eosinophilic cells with eosinophilic granular cytoplasm. The chromaffin tissue is intermingled with adrenocortical tissue. They are formed of adrenaline and noradrenaline secreting cells with different electron density and variable sizes. The zona glomerulosa during estrus shows spherical nuclei with prominent nucleoli. Adrenal gland of pregnant female shows striking differences in ultrastructural features than those observed in the adrenal gland of non-pregnant female. During pregnancy, the cells of zona glomerulosa are hypertrophied and synthetically very active. The lysosomes and few lipid droplets are seen in cytoplasm of cell. The cells of zona fasciculata are large, vacuolated and arranged in cords of polygonal cells having mitochondria with tubular and lamellar cristae. The lipid droplets are observed in close association with smooth endoplasmic reticulum and mitochondria suggesting the role of these organelles in steroidogenesis. The cells of zona reticularis are loaded with lipid droplets. The mitochondria are spherical in shape with collapsed cristae. The cells of zona reticularis are in close association with blood vessels. Few lysosomal bodies are seen in the cytoplasm. Adrenal medulla consists of two types of cells depending on the presence of secretory granules. Nor-epinephrine cells are predominant in the medulla of pregnant bat while epinephrine cells are predominant in the medulla of estrus bat. Key words: Bat, adrenal gland, medulla, ultrastructure, reproductive cycle.