Explore the vast range of titles available.

The endocrine system functions through secretion of signaling substances, hormones, which act on receptors in target cells, tissues, and organs. Hormones are distributed throughout the body via the blood circulation and connective tissue spaces. The actions of the endocrine system are essential in maintenance of homeostasis, development, growth, and reproduction. The endocrine system communicates slowly compared to the body’s other coordinator: the nervous system.

Abstract Background While previous studies indicate that the zonae reticularis (ZR) and glomerulosa (ZG) diminish with aging, little is known about age-related transformations of the zona fasciculata (ZF). Objectives To investigate the morphological and functional changes of the adrenal cortex across adulthood, with emphasis on (i) the understudied ZF and (ii) sexual dimorphisms. Methods We used immunohistochemistry to evaluate the expression of aldosterone synthase (CYP11B2), visinin-like protein 1 (VSNL1), 3β-hydroxysteroid dehydrogenase type II (HSD3B2), 11β-hydroxylase (CYP11B1), and cytochrome b5 type A (CYB5A) in adrenal glands from 60 adults (30 men), aged 18 to 86. Additionally, we employed mass spectrometry to quantify the morning serum concentrations of cortisol, 11-deoxycortisol (11dF), 17α-hydroxyprogesterone, 11-deoxycorticosterone, corticosterone, and androstenedione in 149 pairs of age- and body mass index–matched men and women, age 21 to 95 years. Results The total cortical area was positively correlated with age (r = 0.34, P = 0.008). Both the total (VSNL1-positive) and functional ZG (CYP11B2-positive) areas declined with aging in men (r = −0.57 and −0.67, P < 0.01), but not in women. The CYB5A-positive area declined with age in both sexes (r = −0.76, P < 0.0001). In contrast, the estimated ZF area correlated positively with age in men (r = 0.59, P = 0.0006) and women (r = 0.49, P = 0.007), while CYP11B1-positive area remained unchanged across ages. Serum cortisol, corticosterone, and 11-deoxycorticosterone levels were stable across ages, while 11dF levels increased slightly with age (r = 0.16, P = 0.007). Conclusion Unlike the ZG and ZR, the ZF and the total adrenal cortex areas enlarge with aging. An abrupt decline of the ZG occurs with age in men only, possibly contributing to sexual dimorphism in cardiovascular risk.

Adrenal cortex steroids are essential for body homeostasis, and adrenal insufficiency is a life-threatening condition. Adrenal endocrine activity is maintained through recruitment of subcapsular progenitor cells that follow a unidirectional differentiation path from zona glomerulosa to zona fasciculata (zF). Here, we show that this unidirectionality is ensured by the histone methyltransferase EZH2. Indeed, we demonstrate that EZH2 maintains adrenal steroidogenic cell differentiation by preventing expression of GATA4 and WT1 that cause abnormal dedifferentiation to a progenitor-like state in Ezh2 KO adrenals. EZH2 further ensures normal cortical differentiation by programming cells for optimal response to adrenocorticotrophic hormone (ACTH)/PKA signaling. This is achieved by repression of phosphodiesterases PDE1B, 3A, and 7A and of PRKAR1B. Consequently, EZH2 ablation results in blunted zF differentiation and primary glucocorticoid insufficiency. These data demonstrate an all-encompassing role for EZH2 in programming steroidogenic cells for optimal response to differentiation signals and in maintaining their differentiated state.

Context:Whether primary aldosteronism (PA) is the consequence of a monoclonal or multiclonal process is unclear.Case Description:A 48-year-old man with severe bilateral PA refractory to medical therapy underwent unilateral adrenalectomy of the dominant adrenal. Although computed tomography showed three left-sided cortical nodules, postsurgical histopathology and genetic analysis revealed five different adrenocortical adenomas. Two zona fasciculata (ZF)–like aldosterone-producing adenomas (APAs) each harbored distinct known somatic KCNJ5 mutations (L168R and T158A). A zona glomerulosa–like APA harbored a known CACNA1D G403R somatic mutation, whereas a zona reticularis–like adenoma, which was grossly black in pigmentation with histologic characteristics more associated with cortisol-producing adenomas, expressed CYP11B2, CYP17, and DHEA-ST by immunohistochemistry (IHC) and harbored no known somatic mutations. The fifth adenoma was ZF-type, negative for CYP11B2 and CYP17 IHC, and harbored no known somatic mutations.Conclusions:This case highlights complex intertumor heterogeneity in histology, steroidogenesis, and somatic mutations in multiple adrenocortical adenomas arising in a single patient with PA. These findings suggest that the syndrome of PA can involve heterogeneous and multiclonal functional adrenal adenomas.This study of a patient with multiple aldosterone-producing adenomas revealed complex intertumor heterogeneity in genetics, histology, and steroidogenesis, suggesting a multiclonal process.

Steroid hormones are synthesized through enzymatic reactions using cholesterol as the substrate. In steroidogenic cells, the required cholesterol for steroidogenesis can be obtained from blood circulation or synthesized de novo from acetate. One of the key enzymes that control cholesterol synthesis is 24-dehydrocholesterol reductase (encoded by DHCR24). In humans and rats, DHCR24 is highly expressed in the adrenal gland, especially in the zona fasciculata. We recently reported that DHCR24 was expressed in the mouse adrenal gland’s inner cortex and also found that thyroid hormone treatment significantly upregulated the expression of Dhcr24 in the mouse adrenal gland. In the present study, we showed the cellular expression of DHCR24 in mouse adrenal glands in early postnatal stages. We found that the expression pattern of DHCR24 was similar to the X-zone marker gene 20αHSD in most developmental stages. This finding indicates that most steroidogenic adrenocortical cells in the mouse adrenal gland do not synthesize cholesterol locally. Unlike the 20αHSD-positive X-zone regresses during pregnancy, some DHCR24-positive cells remain present in parous females. Conditional knockout mice showed that the removal of Dhcr24 in steroidogenic cells did not affect the overall development of the adrenal gland or the secretion of corticosterone under acute stress. Whether DHCR24 plays a role in conditions where a continuous high amount of corticosterone production is needed requires further investigation.

Abstract Context Although numerous theories are reported on sex differences in longevity, the underlying biological mechanisms remain unknown. We previously reported that telomere length in the zona reticularis cells of the human adrenal cortex was significantly longer in older than that in younger subjects. However, we could not evaluate sex differences in the telomere lengths. Objective To compare the telomere lengths of adrenocortical and adrenal medullar cells between men and women from infancy through older adulthood. Methods Adrenal glands of 30 male (aged 0 to 100 years) and 25 female (aged 0 to 104 years) autopsied subjects were retrieved from autopsy files. Using quantitative fluorescence in situ hybridization, relative telomere lengths were determined in the parenchymal cells of the 3 adrenocortical zones and medulla. Age-related changes in the weight of adrenal glands were also investigated. Main results Older male subjects (aged 65 years or older) had significantly shorter telomere lengths in zona fasciculata (ZF) cells compared to the corresponding female subjects. In men, older subjects exhibited a significant age-related reduction in adrenal weight; however, no age-related changes in adrenal weight were detected in women. Conclusion Telomere attrition of ZF cells was correlated with adrenal weight reduction in older men but not in older women, suggesting a decreased number of ZF cells in older men. This may help us understand the possible biological mechanisms of sex difference in longevity of humans.

The article presents the results of histological and bacteriological analysis of the adrenal glands in two models of sepsis caused by intraperitoneal administration of Pseudomonas aeruginosa strains 1623 and 5266 to sexually mature male C57BL/6 mice. In both models, histological changes in the adrenal glands in the dynamics of sepsis consist in cell destruction and decrease in the absolute areas of the zona glomerulosa, columnar part of the zona fasciculata, and medulla, the development of venous congestion in the absence of pronounced signs of leukocytic infiltration. Most adrenocortical cells of the zona glomerulosa and chromaffin cells of the medulla show signs of destruction. The columnar part of the zona fasciculata loses normal architectonics, the cells undergo degeneration and apoptosis, a significant part of cells in the deep layers of the zona fasciculata remain intact, but do not show tinctorial and ultrastructural signs of steroidogenesis. The active growth of P. aeruginosa colonies from adrenal homogenates in both models already in the first hours after infection of animals makes it possible to associate the revealed structural changes in the adrenal glands with the direct negative effect of P. aeruginosa , and high levels of mRNA of proinflammatory cytokines in the adrenal tissues raise the question of the possible synthesis of these modulators of inflammation in the adrenal parenchyma of septic animals.

ACTH (i.e., corticotropin) is the principal regulator of the hypothalamus-pituitary-adrenal axis and stimulates steroidogenesis in the adrenal gland via the specific cell-surface melanocortin 2 receptor (MC2R). Here, we generated mice with an inactivation mutation of the MC2R gene to elucidate the roles of MC2R in adrenal development, steroidogenesis, and carbohydrate metabolism. These mice, the last of the knockout (KO) mice to be generated for melanocortin family receptors, provide the opportunity to compare the phenotype of proopiomelanocortin KO mice with that of MC1R-MC5R KO mice. We found that the MC2R KO mutation led to neonatal lethality in three-quarters of the mice, possibly as a result of hypoglycemia. Those surviving to adulthood exhibited macroscopically detectable adrenal glands with markedly atrophied zona fasciculata, whereas the zona glomerulosa and the medulla remained fairly intact. Mutations of MC2R have been reported to be responsible for 25% of familial glucocorticoid deficiency (FGD) cases. Adult MC2R KO mice resembled FGD patients in several aspects, such as undetectable levels of corticosterone despite high levels of ACTH, unresponsiveness to ACTH, and hypoglycemia after prolonged (36 h) fasting. However, MC2R KO mice differ from patients with MC2R-null mutations in several aspects, such as low aldosterone levels and unaltered body length. These results indicate that MC2R is required for postnatal adrenal development and adrenal steroidogenesis and that MC2R KO mice provide a useful animal model by which to study FGD.

The effects of endocrine disrupters of transcriptional control of morphogenesis are poorly studied. Changes in the expression of transcriptional factor PRH and proliferation of adrenal cortical cells were analyzed in pubertal and postpubertal rats exposed prenatally and postnatally to low doses of endocrine disrupter DDT. In rats exposed to DDT, the expression of PRH and proliferation of adrenal cortical cells differed from those in control rats. Association between these parameters was weakened in the zona glomerulosa and zona reticularis and was absent in the zona fasciculata. These findings suggest that exposure to DDT in pre- and postnatal periods impairs the regulation of proliferative processes by transcriptional factor PRH in all zones of rat adrenal cortex, which can be a mechanism of the disruptive action of DDT.