Evolution of a novel adrenal cell type that promotes parental care.

Cell types with specialized functions fundamentally regulate animal behaviour, and yet the genetic mechanisms that underlie the emergence of novel cell types and their consequences for behaviour are not well understood1. Here we show that the monogamous oldfield mouse (Peromyscus polionotus) has recently evolved a novel cell type in the adrenal gland that expresses the enzyme AKR1C18, which converts progesterone into 20α-hydroxyprogesterone. We then demonstrate that 20α-hydroxyprogesterone is more abundant in oldfield mice, where it induces monogamous-typical parental behaviours, than in the closely related promiscuous deer mice (Peromyscus maniculatus). Using quantitative trait locus mapping in a cross between these species, we ultimately find interspecific genetic variation that drives expression of the nuclear protein GADD45A and the glycoprotein tenascin N, which contribute to the emergence and function of this cell type in oldfield mice. Our results provide an example by which the recent evolution of a new cell type in a gland outside the brain contributes to the evolution of social behaviour.

Modulation of circadian glucocorticoid oscillation via adrenal opioid-CXCR7 signaling alters emotional behavior.

Circulating glucocorticoid levels oscillate with a robust circadian rhythm, yet the physiological relevance of this rhythmicity remains unclear. Here, we show that modulation of circadian glucocorticoid oscillation by enhancing its amplitude leads to anxiolytic-like behavior. We observed that mice with adrenal subcapsular cell hyperplasia (SCH), a common histological change in the adrenals, are less anxious than mice without SCH. This behavioral change was found to be dependent on the higher amplitude of glucocorticoid oscillation, although the total glucocorticoid secretion is not increased in these mice. Genetic and pharmacologic experiments demonstrated that intermediate opioid peptides secreted from SCH activate CXCR7, a ß-arrestin-biased G-protein-coupled receptor (GPCR), to augment circadian oscillation of glucocorticoid levels in a paracrine manner. Furthermore, recapitulating this paracrine axis by subcutaneous administration of a synthetic CXCR7 ligand is sufficient to induce anxiolytic-like behavior. Adrenocortical ß-arrestin-biased GPCR signaling is a potential target for modulating circadian glucocorticoid oscillation and emotional behavior.

Corticosterone inhibits GAS6 to govern hair follicle stem-cell quiescence.

Chronic, sustained exposure to stressors can profoundly affect tissue homeostasis, although the mechanisms by which these changes occur are largely unknown. Here we report that the stress hormone corticosterone-which is derived from the adrenal gland and is the rodent equivalent of cortisol in humans-regulates hair follicle stem cell (HFSC) quiescence and hair growth in mice. In the absence of systemic corticosterone, HFSCs enter substantially more rounds of the regeneration cycle throughout life. Conversely, under chronic stress, increased levels of corticosterone prolong HFSC quiescence and maintain hair follicles in an extended resting phase. Mechanistically, corticosterone acts on the dermal papillae to suppress the expression of Gas6, a gene that encodes the secreted factor growth arrest specific 6. Restoring Gas6 expression overcomes the stress-induced inhibition of HFSC activation and hair growth. Our work identifies corticosterone as a systemic inhibitor of HFSC activity through its effect on the niche, and demonstrates that the removal of such inhibition drives HFSCs into frequent regeneration cycles, with no observable defects in the long-term.

Cardiovascular Dynamics in HIV: The Influence of Adrenal Function and Nutritional Status.

This interdisciplinary review explores the intricate nexus between HIV infection, nutrition, adrenal gland function, and cardiovascular health, highlighting a critical aspect of HIV management often overlooked in current literature. With the advent of antiretroviral therapy, the life expectancy of people living with HIV has dramatically improved, transforming HIV into a manageable chronic condition. However, this success brings forth new challenges, notably an increased risk of cardiovascular diseases among people living with HIV. We examine the normal physiology of the adrenal gland, including its role in mineral metabolism, a crucial facet of nutrition. We discuss the evolution of knowledge tying adrenal pathology to cardiovascular disease. We explore the impact of HIV on adrenal gland findings from a gross pathology perspective, as well as the clinical impact of adrenal insufficiency in HIV. The review further elucidates the role of nutrition in this context, considering the double burden of undernutrition and obesity prevalent in regions heavily affected by HIV. By aggregating findings from longitudinal studies and recent clinical trials, the review presents compelling evidence of increased cardiovascular disease among people living with HIV compared with people without HIV. It highlights the critical role of the adrenal glands in regulating nutrient metabolism and its implications for cardiovascular health, drawing attention to the potential for dietary interventions and targeted therapies to mitigate these risks. This review urges a paradigm shift in the management of HIV, advocating for a holistic approach that incorporates nutritional assessment and interventions into routine HIV care to address the complex interplay between HIV, adrenal function, and cardiovascular health. Through this lens, we offer insights into novel therapeutic strategies aimed at reducing cardiovascular risk in people living with HIV, contributing to the ongoing efforts to enhance the quality of life and longevity in this population.

Hyperactivation of sympathetic nerves drives depletion of melanocyte stem cells.

Empirical and anecdotal evidence has associated stress with accelerated hair greying (formation of unpigmented hairs)1,2, but so far there has been little scientific validation of this link. Here we report that, in mice, acute stress leads to hair greying through the fast depletion of melanocyte stem cells. Using a combination of adrenalectomy, denervation, chemogenetics3,4, cell ablation and knockout of the adrenergic receptor specifically in melanocyte stem cells, we find that the stress-induced loss of melanocyte stem cells is independent of immune attack or adrenal stress hormones. Instead, hair greying results from activation of the sympathetic nerves that innervate the melanocyte stem-cell niche. Under conditions of stress, the activation of these sympathetic nerves leads to burst release of the neurotransmitter noradrenaline (also known as norepinephrine). This causes quiescent melanocyte stem cells to proliferate rapidly, and is followed by their differentiation, migration and permanent depletion from the niche. Transient suppression of the proliferation of melanocyte stem cells prevents stress-induced hair greying. Our study demonstrates that neuronal activity that is induced by acute stress can drive a rapid and permanent loss of somatic stem cells, and illustrates an example in which the maintenance of somatic stem cells is directly influenced by the overall physiological state of the organism.

Comparative assessment of CacyBP/SIP, ß-catenin and cannabinoid receptors in the adrenals of hypertensive rats.

Taking into account homeostatic disorders resulting from arterial hypertension and the key importance of CacyBP/SIP, ß-catenin and endocannabinoids in the functioning of many organs, it was decided to assess the presence and distribution of CacyBP/SIP, ß-catenin, CB1 and CB2 in the adrenal glands of hypertensive rats of various aetiology. The study was conducted on the adrenal glands of rats with spontaneous and renovascular hypertension. The expression of CacyBP/SIP, ß-catenin, CB1 and CB2 was detected by immunohistochemistry and real-time PCR method. The results of the present study revealed both lower gene expression and immunoreactivity of CacyBP/SIP in the adrenal glands of all hypertensive groups compared to the normotensive rats. This study demonstrated a reduction in the immunoreactivity and expression of the ß-catenin, CB1 and CB2 genes in the adrenals of 2K1C rats. While in SHR, the reaction showing ß-catenin and CB1 was very weak or negative, and the expression of CB2 in the adrenal glands of these rats increased. The results of this study show, for the first time, marked differences in the expression of CacyBP/SIP, ß-catenin and CB1 and CB2 cannabinoid receptors in the adrenal glands of rats with primary (SHR) and secondary hypertension (2K1C).

The ex vivo perfused mouse adrenal gland-a new model to study aldosterone secretion.

Aldosterone is a steroid hormone that is important for maintaining the volume and ionic composition of extracellular fluids and is produced in the zona glomerulosa of the adrenal cortex. The basic mechanisms controlling aldosterone secretion are known. However, more detailed studies on the regulation of aldosterone secretion often fail due to the lack of suitable models: although secretion can be studied in cultured adrenocortical cells under defined conditions, the differentiation status of the cells is difficult to control and the complex anatomy of the adrenal cortex is lost. In living animals, the physiological context is intact, but the influences are manifold and the examination conditions cannot be sufficiently controlled. One method that closes the gap between cell models and studies in living animals is the isolated perfused adrenal gland. In the past, this method has provided important data on the pathophysiology of adrenal glands from larger animals, but the technique was not used in mice. Here, we developed a method for isolation and perfusion of the mouse adrenal gland to study aldosterone secretion. This technique preserves the complex anatomical and functional context of the mouse adrenal cortex, to ensure defined experimental conditions and to minimize extra-adrenal influences. Initial series of experiments with the ex vivo perfused mouse adrenal gland show that this model offers the possibility for unique insights into pathophysiological regulatory principles and is suitable for the use of genetically modified mouse models.

Beyond symptomatology: A comparative analysis of unilateral and bilateral macronodular mild autonomous cortisol secretion.

OBJECTIVE: To investigate the clinical, laboratory findings and signal intensity index (SII) on magnetic resonance imaging (MRI) of patients with bilateral and unilateral macronodular mild autonomous cortisol secretion (MACS). PATIENTS AND MEASUREMENTS: Clinical and laboratory findings of 81 patients with MACS were examined from retrospective records. SII of adenomas and internodular areas were evaluated by MRI. The unilateral group included patients with an adrenal macronodule (≥1 cm) in a single adrenal gland, while the bilateral group included patients with at least one macronodule in both adrenal glands. RESULTS: In total, 46 patients were in the unilateral (57%), while 35 (43%) patients were in the bilateral groups. The dehydroepiandrosterone sulphate (DHEA-S) level was lower in the unilateral than in the bilateral group (p < .001). The presence of type 2 diabetes mellitus (T2DM), glycosylated haemoglobin (HbA1c) and low-density lipoprotein (LDL) concentrations were higher in the bilateral group (p < .05). However, no significant difference was detected in terms of adrenocorticotropic hormone (ACTH) and overnight 1 mg dexamethasone suppression test (DST) between the two groups (p > .05). There was no difference in SII between adenomas within the same patient, as well as between the unilateral and bilateral groups (p > .05). Logistic regression analysis based on the differentiation between unilateral and bilateral macronodular MACS demonstrated that DHEA-S, HbA1c and LDL concentrations were associated factors. CONCLUSION: DHEA-S levels may not be as suppressed in patients with bilateral macronodular MACS as compared to those with unilateral adenoma. T2DM and hypercholesterolaemia have a higher frequency in bilateral patients. However, ACTH, overnight 1 mg DST and SII may not provide additional information for differentiation of bilaterality and unilaterality.

Feasibility Study of Single-Photon Emission Computed Tomography with Iodine-123 Labeled Metaiodobenzylguanidine for Preclinical Evaluation of Labetalol as a ß-Adrenergic Receptor Blocker.

Among clinically used radiopharmaceuticals, iodine-123 labeled metaiodobenzylguanidine ([123I]mIBG) serves for diagnosing neuroendocrine tumors and obtaining images of myocardial sympathetic innervation. mIBG, a structural analogue of norepinephrine (NE), a neurotransmitter acting in peripheral and central nerves, follows a pathway similar to NE, transmitting signals through the NE transporter (NET) located at synaptic terminals. It moves through the body without decomposing, enabling noninvasive image evaluation. In this study, we aimed to quantify [123I]mIBG uptake in the adrenal glands using small animal single-photon emission computed tomography/computed tomography (SPECT/CT) images post [123I]mIBG administration. We investigated the possibility of assessing the effectiveness of ß-adrenergic receptor blockers by quantifying SPECT/CT images and biodistribution results to determine the degree of [123I]mIBG uptake in the adrenal glands treated with labetalol, a known ß-adrenergic receptor blocker. Upon intravenous administration of [123I]mIBG to mice, SPECT/CT images were acquired over time to confirm the in vivo distribution pattern, revealing a clear uptake in the adrenal glands. Labetalol inhibited the uptake of [123I]mIBG in cell lines expressing NET. A decrease in [123I]mIBG uptake in the adrenal glands was observed in the labetalol-treated group compared with the normal group through SPECT/CT imaging and biodistribution studies. These results demonstrate that SPECT/CT imaging with [123I]mIBG could be applicable for evaluating the preclinical efficacy of new antihypertensive drug candidates such as labetalol, a ß-adrenergic receptor blocker.

Effect of resuscitation of cryopreserved porcine adrenal glands at 26 °C on their recovery and functioning under xenotransplantation.

The study is devoted to the effect of lowered resuscitation temperature (26 °C) on cryopreserved porcine adrenal glands functional activity in vitro and in vivo under xenotransplantation. The adrenals were collected from newborn pigs, cryopreserved with 5 % DMSO at a rate of 1 °C/min, resuscitated at 26 or 37 °C for 48 h (5 % CO2, DMEM), embedded into small intestinal submucosa, and transplanted to bilaterally adrenalectomized rats. It has been shown that the glands resuscitated at 26 °C have suppressed free-radical processes and can produce cortisol and aldosterone in vitro, and may lead to elevated blood levels of these hormones. Moreover, the adrenal grafts maintain blood glucose levels and promote the formation of glycogen stores. Thus, the resuscitation at 26 °C can improve the quality of grafts and favor the introduction and application of the cryopreserved organs and tissues for transplantation in clinical and experimental practice.

Determination of three C18-oxygenated steroids in adrenal lesion segments in primary aldosteronism by super-selective adrenal venous sampling and LC/ESI-MS/MS.

Super-selective adrenal venous sampling (ssAVS) can collect the adrenal tributary venous blood in the aldosterone (ALD)-hypersecreting segments in primary aldosteronism. The concentrations of the C18-oxygenated steroids, especially 18-oxocortisol (18-oxoF), in the lesion segments might be more useful indices than those in the peripheral or adrenal central veins (current candidate indexes) for the differential diagnosis of unilateral ALD-producing adenoma (APA) and bilateral adrenal hyperplasia (BAH). To verify this hypothesis, we developed a liquid chromatography/electrospray ionization-tandem mass spectrometry (LC/ESI-MS/MS) method for simultaneously quantifying ALD, 18-oxoF and 18-hydroxycortisol in the adrenal tributary venous serum sample collected by ssAVS (ssAVS serum) and compared their concentrations between APA and BAH patients. Only deproteinization was required for a 10 µl sample prior to the LC/ESI-MS/MS analysis. Endogenous corticoids did not interfere with the quantifications, and the intra-assay and interassay precisions (≤ 8.3%) and accuracies (94.2-102.7%) were acceptable. The clinical study revealed that the 18-oxoF concentration was significantly higher in the ALD-producing tumor tissues (from APA patients) than in the hyperplastic tissues (from BAH patients). However, in conclusion, the 18-oxoF concentration in the ssAVS serum sample can be a rough indication but cannot be decisive for the differential diagnosis between APA and BAH owing to the significant individual difference.

The Role of the Gap Junction Protein Connexin in Adrenal Gland Tumorigenesis.

Gap junctions (GJs) are important in the regulation of cell growth, morphology, differentiation and migration. However, recently, more attention has been paid to their role in the pathogenesis of different diseases as well as tumorigenesis, invasion and metastases. The expression pattern and possible role of connexins (Cxs), as major GJ proteins, under both physiological and pathological conditions in the adrenal gland, were evaluated in this review. The databases Web of Science, PubMed and Scopus were searched. Studies were evaluated if they provided data regarding the connexin expression pattern in the adrenal gland, despite current knowledge of this topic not being widely investigated. Connexin expression in the adrenal gland differs according to different parts of the gland and depends on ACTH release. Cx43 is the most studied connexin expressed in the adrenal gland cortex. In addition, Cx26, Cx32 and Cx50 were also investigated in the human adrenal gland. Cx50 as the most widespread connexin, along with Cx26, Cx29, Cx32, Cx36 and Cx43, has been expressed in the adrenal medulla with distinct cellular distribution. Considerable effort has recently been directed toward connexins as therapeutically targeted molecules. At present, there exist several viable strategies in the development of potential connexin-based therapeutics. The differential and hormone-dependent distribution of gap junctions within adrenal glands, the relatively large gap junction within this gland and the increase in the gap junction size and number following hormonal treatment would indicate that gap junctions play a pivotal role in cell functioning in the adrenal gland.

A Humanized and Viable Animal Model for Congenital Adrenal Hyperplasia-CYP21A2-R484Q Mutant Mouse.

Congenital Adrenal Hyperplasia (CAH) is an autosomal recessive disorder impairing cortisol synthesis due to reduced enzymatic activity. This leads to persistent adrenocortical overstimulation and the accumulation of precursors before the blocked enzymatic step. The predominant form of CAH arises from mutations in CYP21A2, causing 21-hydroxylase deficiency (21-OHD). Despite emerging treatment options for CAH, it is not always possible to physiologically replace cortisol levels and counteract hyperandrogenism. Moreover, there is a notable absence of an effective in vivo model for pre-clinical testing. In this work, we developed an animal model for CAH with the clinically relevant point mutation p.R484Q in the previously humanized CYP21A2 mouse strain. Mutant mice showed hyperplastic adrenals and exhibited reduced levels of corticosterone and 11-deoxycorticosterone and an increase in progesterone. Female mutants presented with higher aldosterone concentrations, but blood pressure remained similar between wildtype and mutant mice in both sexes. Male mutant mice have normal fertility with a typical testicular appearance, whereas female mutants are infertile, exhibit an abnormal ovarian structure, and remain in a consistent diestrus phase. Conclusively, we show that the animal model has the potential to contribute to testing new treatment options and to prevent comorbidities that result from hormone-related derangements and treatment-related side effects in CAH patients.

Primary bilateral macronodular adrenocortical hyperplasia (PBMAH) patient with ARMC5 mutations.

BACKGROUND: Primary bilateral macronodular adrenocortical hyperplasia (PBMAH) is a highly heterogeneous disease with divergent manifestations ranging from asymptomatic subclinical Cushing syndrome (CS) to overt Cushing syndrome with severe complications. ARMC5 mutations occur in 20 to 55% PBMAH patients usually with more severe phenotypes. Different ARMC5 mutations might be associated with diverse phenotypes of PBMAH. CASE PRESENTATION: A 39-year-old man was admitted to our hospital with progressive weight gain and severe hypertension. He presented typical CS and its classical metabolic and bone complications like hypertension and osteoporosis. The laboratory results showed high levels of cortisol and low levels of ACTH. Low- and high-dosed dexamethasone suppression tests were negative. Contrast-enhanced computed tomography (CT) revealed multiple bilateral irregular macronodular adrenal masses. Adrenal venous sampling (AVS) confirmed that the right adrenal gland with larger nodules secreted more hormone that the left side did. Right adrenalectomy and subsequent contralateral subtotal resection were conducted. His blood pressure and CS symptoms as well as comorbidities including backache and muscle weakness improved. Whole exome sequencing identified one ARMC5 germline mutation (c.1855C > T, p. R619*), five ARMC5 somatic mutations (four novel mutations) in his right and left adrenal nodules. CONCLUSIONS: This PBMAH patient was identified with one ARMC5 germline mutation and five different somatic ARMC5 mutations (four novel mutations) in the different nodules of the bilateral adrenal masses. AVS combined with CT imagine could be helpful to determine the dominant side for adrenalectomy. Genetic testing is important for the diagnosis and management of the patient with PBMAH.

The protective effect of N-acetyl cysteine against selenium toxicity and gamma irradiation in rats.

N-acetyl cysteine (NAC) is a nutritional supplement and greatly applied as an antioxidant in vivo and in vitro. Therefore, this study aimed to assess the metabolic and antioxidant protective effect of NAC against selenium (Se) toxicity and gamma irradiation in rats by measuring biochemical and molecular parameters. This study was conducted on sixty rats divided into six equal different groups; control, NAC, Rad, Se, Rad + NAC, and Se + NAC groups. Oxidative/nitrosative makers (LPO, NO, and NOS), antioxidants status markers (GSH, GPx, and SOD), liver metabolic markers (LDH, SDH, and ATP), and plasma metabolic markers (Glucose, total cholesterol, and total proteins) were measured using commercial colorimetric kits while plasma corticosterone concentration was measured using commercial ELISA kit. Also, Levels of NR3C1 and Glut-2 genes expression using reverse transcription-quantitative polymerase chain reaction were done. Our results revealed that Se toxicity and gamma irradiation induced significant increases in oxidative/nitrosative stress markers and a significant decrease in antioxidant status markers in the liver and adrenal tissues. Moreover, metabolic disorders were recorded as manifested by elevation of plasma ALT, Albumin, glucose and cholesterol, and decrease in protein levels associated with a significant increase in corticosterone concentration. This was also accompanied by a significant decrease in SDH activity and ATP production in the hepatic tissue. Molecular analysis showed a marked increase in NR3C1 mRNA and decrease in Glut-2 mRNA in liver tissue. However, NAC supplementation attenuated the changes induced by these toxins. Finally, we could conclude that, oral supplementation of NAC can modulate the metabolic disturbances and has protective effects in rats exposed to Se toxicity and gamma irradiation.

TRPV1 inactivation alters core body temperature and serum corticosterone levels: Impacts on clock genes expression in the liver and adrenal glands.

PURPOSE: TRPV1 desensitization or blockade promotes hyperthermia in rodents. Daily changes in core body temperature (Tc), spontaneous locomotor activity (SLA), and glucocorticoids are temporal cues for peripheral clocks. Thus, this study aimed to evaluate the effects of both desensitization and blockade of TRPV1 on Tc, SLA, blood corticosterone, and the clock genes Per1 and Bmal1 in the liver and adrenal. METHODS AND RESULTS: Resiniferatoxin (RTX, 20 µg kg-1) known to desensitize the intra-abdominal TRPV1 channels was i. p. administered in adult male rats. One day after, RTX rats displayed higher Tc than vehicle rats (control) in the light and dark phases. RTX rats showed higher corticosterone at zeitgeber time (ZT) 6 and ZT12 compared to ZT0. Control rats showed a rise in corticosterone at ZT12. RTX abolished the Per1 peak in both the liver and adrenal glands, whereas it enhanced the peak of Bmal1 expression in the liver and decreased it in adrenal glands. Circadian variation in Tc and SLA was unaffected despite higher Tc being found along the light phase up to 5 days after RTX injection. Acute blockade of TRPV1 with the antagonist AMG-517 injected at ZT0 increased Tc and reduced corticosterone without affecting SLA. In the liver, while AMG-517 did not affect Per1, it increased Bmal1 mRNA. In adrenal glands, AMG-517 increased Per1 and did not affect Bmal1 expression. Although rats exposed to a 60-min 34 °C environment showed similar hyperthermia to that observed in AMG-517 rats, neither corticosterone nor liver nor adrenal clock genes changed. CONCLUSIONS: Inactivation of TRPV1 by abdominal desensitization or by antagonism alters the time-of-day changes of clock genes expression in the liver and adrenal, as well as corticosterone. TRPV1 may be necessary for signaling cyclical temporal cues for clock genes in the periphery but less critical for the circadian profile of Tc and SLA.

Transcriptome Profile of the Rat Adrenal Gland: Parenchymal and Interstitial Cells.

The homeostasis of the adrenal gland plays a decisive role in its proper functioning, both in non-stressful conditions and under the influence of various types of stress. This consists of interactions between all types of cells that make up the organ, including parenchymal and interstitial cells. The amount of available information on this subject in the rat adrenal glands under non-stressful conditions is insufficient; the aim of the research was to determine the expression of marker genes for rat adrenal cells depending on their location. The material for the study consisted of adrenal glands taken from intact adult male rats that were separated into appropriate zones. Transcriptome analysis by means of Affymetrix® Rat Gene 2.1 ST Array was used in the study, followed by real-time PCR validation. Expression analysis of interstitial cell marker genes revealed both the amount of expression of these genes and the zone in which they were expressed. The expression of marker genes for fibroblasts was particularly high in the cells of the ZG zone, while the highest expression of specific macrophage genes was observed in the adrenal medulla. The results of this study, especially with regard to interstitial cells, provide a so far undescribed model of marker gene expression of various cells, both in the cortex and medulla of the sexually mature rat adrenal gland. The interdependence between parenchymal and interstitial cells creates a specific microenvironment that is highly heterogeneous within the gland with respect to some of the interstitial cells. This phenomenon most likely depends on the interaction with the differentiated parenchymal cells of the cortex, as well as the medulla of the gland.

DHCR24, a Key Enzyme of Cholesterol Synthesis, Serves as a Marker Gene of the Mouse Adrenal Gland Inner Cortex.

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.

Effects of testis testosterone deficiency on gene expression in the adrenal gland and skeletal muscle of ducks.

1. Testosterone has an anabolic effect on skeletal muscle. The testes produce most of the testosterone in vivo, while the adrenal glands contribute smaller amounts. When testis testosterone is deficient the adrenal gland increases steroid hormone synthesis, which is referred to as compensatory testicular adaptation (CTA).2. To reveal the effects of testis testosterone deficiency on adrenal steroid hormones synthesis and skeletal muscle development, gene expression related to adrenal steroid hormones synthesis and skeletal muscle development were determined by RNA-seq.3. The results showed that castrating male ducks had significant effects on their body weight but no significant impact on cross-sectional area (CSA) or density of pectoral muscle fibres. In skeletal muscle protein metabolism, expression levels of the catabolic gene atrogin1/MAFbx and the anabolic gene eEF2 were significantly higher, with concomitant increases after castration. The adrenal glands' alteration of the steroid hormone 11ß-hydroxylase (CYP11B1) was significantly lower following castration.4. Expression pattern analysis showed that the adrenal glands' glucocorticoid receptor (NR3C1/GR) had a potential regulatory relationship with the skeletal muscle-related genes (Pax7, mTOR, FBXO32, FOXO3, and FOXO4).5. The data showed that castration affected muscle protein metabolism, adrenal steroid and testosterone synthesis. In addition, it was speculated that, after castration, steroid hormones produced by the adrenal gland could have a compensatory effect, which might mediate the changes in skeletal muscle protein metabolism and development.

Tyrosine hydroxylase conditional KO mice reveal peripheral tissue-dependent differences in dopamine biosynthetic pathways.

Dopamine (DA) exerts well-known functions in the brain as a neurotransmitter. In addition, it plays important physiological roles in peripheral organs, but it is largely unknown how and where peripheral DA is synthesized and regulated. Catecholamines in peripheral tissues are either produced within the tissue itself and/or derived from sympathetic neurons, which release neurotransmitters for uptake by peripheral tissues. To evaluate DA-producing ability of each peripheral tissue, we generated conditional KO mice (cKO mice) in which the tyrosine hydroxylase (TH) gene is ablated in the sympathoadrenal system, thus eliminating sympathetic neurons as a DA source. We then examined the alterations in the noradrenaline (NA), DA, and 3,4-dihydroxyphenylalanine (DOPA) contents in peripheral organs and performed immunohistochemical analyses of TH-expressing cells. In the heart and pancreas of cKO mice, both the TH protein and NA levels were significantly decreased, and the DA contents were decreased in parallel with NA contents, indicating that the DA supply originated from sympathetic neurons. We found TH-immunoreactive cells in the stomach and lung, where the TH protein showed a decreasing trend, but the DA levels were not decreased in cKO mice. Moreover, we found a significant correlation between the DA content in the kidney and the plasma DOPA concentration, suggesting that the kidney takes up DOPA from blood to make DA. The aforementioned data unravel differences in the DA biosynthetic pathway among tissues and support the role of sympathetic neurons as a DA supplier.