Adrenal Expression Research Articles

Strain-based and sex-biased differences in adrenal and pancreatic gene expression between KK/HlJ and C57BL/6\u2009J mice

BackgroundThe ever-increasing prevalence of diabetes and associated comorbidities serves to highlight the necessity of biologically relevant small-animal models to investigate its etiology, pathology and treatment. Although the C57BL/6 J model is amongst the most widely used mouse model due to its susceptibility to diet-induced obesity (DIO), there are a number of limitations namely [1] that unambiguous fasting hyperglycemia can only be achieved via dietary manipulation and/or chemical ablation of the pancreatic beta cells. [2] Heterogeneity in the obesogenic effects of hypercaloric feeding has been noted, together with sex-dependent differences, with males being more responsive. The KK mouse strain has been used to study aspects of the metabolic syndrome and prediabetes. We recently conducted a study which characterized the differences in male and female glucocentric parameters between the KK/HlJ and C57BL/6 J strains as well as diabetes-related behavioral differences (Inglis et al. 2019). In the present study, we further characterize these models by examining strain- and sex-dependent differences in pancreatic and adrenal gene expression using Affymetrix microarray together with endocrine-associated serum analysis.ResultsIn addition to strain-associated differences in insulin tolerance, we found significant elevations in KK/HlJ mouse serum leptin, insulin and aldosterone. Additionally, glucagon and corticosterone were elevated in female mice of both strains. Using 2-factor ANOVA and a significance level set at 0.05, we identified 10,269 pancreatic and 10,338 adrenal genes with an intensity cut-off of ≥2.0 for all 4 experimental groups. In the pancreas, gene expression upregulated in the KK/HlJ strain related to increased insulin secretory granule biofunction and pancreatic hyperplasia, whereas ontology of upregulated adrenal differentially expressed genes (DEGs) related to cell signaling and neurotransmission. We established a network of functionally related DEGs commonly upregulated in both endocrine tissues of KK/HlJ mice which included the genes coding for endocrine secretory vesicle biogenesis and regulation: PCSK2, PCSK1N, SCG5, PTPRN, CHGB and APLP1. We also identified genes with sex-biased expression common to both strains and tissues including the paternally expressed imprint gene neuronatin.ConclusionOur novel results have further characterized the commonalities and diversities of pancreatic and adrenal gene expression between the KK/HlJ and C57BL/6 J strains as well as differences in serum markers of endocrine physiology.

SUN-161 Primary Aldosteronism and Klinefelter’s Syndrome: Two Cases

Background: Primary aldosteronism (PA) is more common than expected. Aberrant adrenal expression of LH receptor in patients with PA has been reported, however, its physiological role on the development of PA is still unknown. Herein, we report two unique cases of PA in patients with untreated Klinefelter’s syndrome, characterized as increased serum LH, suggesting a possible contribution of the syndrome to PA development. Clinical Cases: Case 1 was a 39-year-old man with obesity and hypertension since his 20s. His plasma aldosterone concentration (PAC) and renin activity (PRA) were 220 pg/mL and 0.4 ng/mL/h, respectively. He was diagnosed as having bilateral PA by confirmatory tests and adrenal venous sampling (AVS). Klinefelter’s syndrome was suspected as he showed gynecomastia and small testes, and it was confirmed on the basis of a low serum total testosterone level (57.3 ng/dL), high serum LH level (50.9 mIU/mL), and chromosome analysis. Case 2 was a 28-year-old man who had untreated Klinefelter’s syndrome diagnosed in his childhood and a two-year history of hypertension and hypokalemia. PAC and PRA were 247 pg/mL and 0.3 ng/mL/h, respectively. He was diagnosed as having a 10 mm-sized aldosterone-producing adenoma (APA) by AVS. In the APA, immunohistochemical analysis showed co-expression of LH receptor and CYP11B2. Conclusion: Our cases of untreated Klinefelter’s syndrome complicated with PA suggest that increased serum LH levels and adipose tissues, caused by primary hypogonadism, could contribute to PA development. The possible complication of PA in hypertensive patients with Klinefelter’s syndrome should be carefully considered.

Human DENND1A.V2 Drives Cyp17a1 Expression and Androgen Production in Mouse Ovaries and Adrenals.

The DENND1A locus is associated with polycystic ovary syndrome (PCOS), a disorder characterized by androgen excess. Theca cells from ovaries of PCOS women have elevated levels of a DENND1A splice variant (DENND1A.V2). Forced expression of this variant in normal theca cells increases androgen biosynthesis and CYP17A1 expression, whereas knockdown of the transcript in PCOS theca cells reduced androgen production and CYP17A1 mRNA. We attempted to create a murine model of PCOS by expressing hDENND1A.V2 using standard transgenic approaches. There is no DENND1A.V2 protein equivalent in mice, and the murine Dennd1a gene is essential for viability since Dennd1a knockout mice are embryonically lethal, suggesting that Dennd1a is developmentally critical. Three different hDENND1A.V2 transgenic mice lines were created using CMV, Lhcgr, and TetOn promoters. The hDENND1A.V2 mice expressed hDENND1A.V2 transcripts. While hDENND1A.V2 protein was not detectable by Western blot analyses, appropriate hDENND1A.V2 immunohistochemical staining was observed. Corresponding Cyp17a1 mRNA levels were elevated in ovaries and adrenals of CMV transgenic mice, as were plasma steroid production by theca interstitial cells isolated from transgenic ovaries. Even though the impact of robust hDENND1A.V2 expression could not be characterized, our findings are consistent with the notion that elevated hDENND1A.V2 has a role in the hyperandrogenemia of PCOS.

Exploration of cardiometabolic and developmental significance of angiotensinogen expression by cells expressing the leptin receptor or agouti-related peptide.

Angiotensin II (ANG II) Agtr1a receptor (AT1A) is expressed in cells of the arcuate nucleus of the hypothalamus that express the leptin receptor (Lepr) and agouti-related peptide (Agrp). Agtr1a expression in these cells is required to stimulate resting energy expenditure in response to leptin and high-fat diets (HFDs), but the mechanism activating AT1A signaling by leptin remains unclear. To probe the role of local paracrine/autocrine ANG II generation and signaling in this mechanism, we bred mice harboring a conditional allele for angiotensinogen (Agt, encoding AGT) with mice expressing Cre-recombinase via the Lepr or Agrp promoters to cause cell-specific deletions of Agt (AgtLepr-KO and AgtAgrp-KO mice, respectively). AgtLepr-KO mice were phenotypically normal, arguing against a paracrine/autocrine AGT signaling mechanism for metabolic control. In contrast, AgtAgrp-KO mice exhibited reduced preweaning survival, and surviving adults exhibited altered renal structure and steroid flux, paralleling previous reports of animals with whole body Agt deficiency or Agt disruption in albumin (Alb)-expressing cells (thought to cause liver-specific disruption). Surprisingly, adult AgtAgrp-KO mice exhibited normal circulating AGT protein and hepatic Agt mRNA expression but reduced Agt mRNA expression in adrenal glands. Reanalysis of RNA-sequencing data sets describing transcriptomes of normal adrenal glands suggests that Agrp and Alb are both expressed in this tissue, and fluorescent reporter gene expression confirms Cre activity in adrenal gland of both Agrp-Cre and Alb-Cre mice. These findings lead to the iconoclastic conclusion that extrahepatic (i.e., adrenal) expression of Agt is critically required for normal renal development and survival.

Prolonged treatment with the synthetic glucocorticoid methylprednisolone affects adrenal steroidogenic function and response to inflammatory stress in the rat

Synthetic glucocorticoids are widely prescribed for the treatment of numerous inflammatory and autoimmune diseases and they can also affect the way the adrenal gland produces endogenous glucocorticoids. Indeed, patients undergoing synthetic glucocorticoid treatment can develop adrenal insufficiency, a condition characterised by reduced responsiveness of the adrenal to ACTH stimulation or stressors (e.g. surgical or inflammatory stress). To better elucidate the long-term effect of synthetic glucocorticoids treatment and withdrawal on adrenal function, we have investigated the long-term effects of prolonged treatment with methylprednisolone on HPA axis dynamics and on the adrenal steroidogenic pathway, both in basal conditions and in response to an inflammatory stress (lipopolysaccharide, LPS).We have found that 5-days treatment with methylprednisolone suppresses basal ACTH and corticosterone secretion, as well as corticosterone secretion in response to a high dose of ACTH, and down-regulates key genes in the adrenal steroidogenic pathway, including StAR, MRAP, CYP11a1 and CYP11b1. These effects were paralleled by changes in the adrenal expression of transcription factors regulating steroidogenic gene expression, as well as changes in the expression of adrenal clock genes. Importantly, 5 days after withdrawal of the treatment, ACTH levels are restored, yet basal levels of corticosterone, as well as most of the key steroidogenic genes and their regulators, remain down regulated. We also show that, although 5-days treatment with methylprednisolone reduces the corticosterone response to LPS, an increase in intra-adrenal pro-inflammatory cytokine gene expression was observed.Our data suggests that the steroidogenic pathway is directly affected by synthetic glucocorticoid treatment in the long-term, presumably via a mechanism involving activation of the glucocorticoid receptor. Furthermore, our data suggests a pro-inflammatory effect of synthetic glucocorticoids treatment in the adrenal gland.

Evidence in Favor of an Alternative Glucocorticoid Synthesis Pathway During Acute Experimental Chagas Disease.

It is well-established that infectious stress activates the hypothalamus–pituitary–adrenal axis leading to the production of pituitary adrenocorticotropin (ACTH) and adrenal glucocorticoids (GCs). Usually, GC synthesis is mediated by protein kinase A (PKA) signaling pathway triggered by ACTH. We previously demonstrated that acute murine Chagas disease courses with a marked increase of GC, with some data suggesting that GC synthesis may be ACTH-dissociated in the late phase of this parasitic infection. Alternative pathways of GC synthesis have been reported in sepsis or mental diseases, in which interleukin (IL)-1β, prostaglandin E2 (PGE2), and/or cAMP-activated guanine nucleotide exchange factor 2 (EPAC2) are likely to play a role in this regard. Accordingly, we have searched for the existence of an ACTH-independent pathway in an experimental model of a major parasitic disease like Chagas disease, in addition to characterizing potential alternative pathways of GC synthesis. To this end, C57BL/6 male mice were infected with T. cruzi (Tc), and evaluated throughout the acute phase for several parameters, including the kinetic of GC and ACTH release, the adrenal level of MC2R (ACTH receptor) expression, the p-PKA/PKA ratio as ACTH-dependent mechanism of signal transduction, as well as adrenal expression of IL-1β and its receptor, EPAC2 and PGE2 synthase. Our results reveal the existence of two phases involved in GC synthesis during Tc infection in mice, an initial one dealing with the well-known ACTH-dependent pathway, followed by a further ACTH-hyporesponsive phase. Furthermore, inflamed adrenal microenvironment may tune the production of intracellular mediators that also operate upon GC synthesis, like PGE2 synthase and EPAC2, as emerging driving forces for GC production in the advanced course of Tc infection. In essence, GC production seems to be associated with a biphasic action of PGE2, suggesting that the effect of PGE2/cAMP in the ACTH-independent second phase may be mediated by EPAC2.

MiR-24 inhibits oligodendrocyte precursor cell differentiation after spinal injury by targeting adrenal medulla.

Oligodendrocyte precursor cells (OPCs) differentiate into oligodendrocytes (OLs) that provide nutrients to neurons. Adrenal medulla is (ADM) involved in nerve damage. MiR-24 participates in various diseases. However, the regulation and mechanism of miR-24 in oligodendrocyte precursor cell differentiation after spinal injury is unclear. MATERIALS AND METHODS: Wistar rats were divided into sham operation group and model group. Real Time-PCR detects miR-24, PDGFRa and NG2 and MBP expression. OPC cells were cultured and divided into control group, miR-24 group, and si-miR-24 group followed by analysis of miR-24 expression by Real Time-PCR, expression of PDGFRa, NG2 and MBP by Western blot, as well as ADM content and secretion of IL-6 and TNF-α by enzyme-linked immunosorbent assay (ELISA). Expression of miR-24, PDGFRa, and NG2 was increased in the model group and MBP and ADM expression was decreased with increased secretion of IL-6 and TNF-α. Compared with control group, the difference was statistically significant (p<0.05). Upregulation of miR-24 promoted the expression of PDGFRa and NG2, decreased MBP and ADM level, and increased IL-6 and TNF-α secretion. Compared with control group, the difference was statistically significant (p<0.05). Downregulation of miR-24 reversed the above changes, and the difference was statistically significant (p<0.05). MiR-24 expression is increased in spinal injury. Upregulation of miR-24 expression reduces adrenal medulla expression and inhibits oligodendrocyte precursor cell differentiation.

Primary aldosteronism in Klinefelter's syndrome: two cases.

SummaryPrimary aldosteronism (PA) is more common than expected. Aberrant adrenal expression of luteinizing hormone (LH) receptor in patients with PA has been reported; however, its physiological role on the development of PA is still unknown. Herein, we report two unique cases of PA in patients with untreated Klinefelter’s syndrome, characterized as increased serum LH, suggesting a possible contribution of the syndrome to PA development. Case 1 was a 39-year-old man with obesity and hypertension since his 20s. His plasma aldosterone concentration (PAC) and renin activity (PRA) were 220 pg/mL and 0.4 ng/mL/h, respectively. He was diagnosed as having bilateral PA by confirmatory tests and adrenal venous sampling (AVS). Klinefelter’s syndrome was suspected as he showed gynecomastia and small testes, and it was confirmed on the basis of a low serum total testosterone level (57.3 ng/dL), high serum LH level (50.9 mIU/mL), and chromosome analysis. Case 2 was a 28-year-old man who had untreated Klinefelter’s syndrome diagnosed in his childhood and a 2-year history of hypertension and hypokalemia. PAC and PRA were 247 pg/mL and 0.3 ng/mL/h, respectively. He was diagnosed as having a 10 mm-sized aldosterone-producing adenoma (APA) by AVS. In the APA, immunohistochemical analysis showed co-expression of LH receptor and CYP11B2. Our cases of untreated Klinefelter’s syndrome complicated with PA suggest that increased serum LH levels and adipose tissues, caused by primary hypogonadism, could contribute to PA development. The possible complication of PA in hypertensive patients with Klinefelter’s syndrome should be carefully considered.Learning points:The pathogenesis of primary aldosteronism is still unclear.Expression of luteinizing hormone receptor has been reported in aldosterone-producing adenoma.Serum luteinizing hormone, which is increased in patients with Klinefelter’s syndrome, might contribute to the development of primary aldosteronism.

Maternal betaine suppresses adrenal expression of cholesterol trafficking genes and decreases plasma corticosterone concentration in offspring pullets

BackgroundLaying hens supplemented with betaine demonstrate activated adrenal steroidogenesis and deposit higher corticosterone (CORT) in the egg yolk. Here we further investigate the effect of maternal betaine on the plasma CORT concentration and adrenal expression of steroidogenic genes in offspring pullets.ResultsMaternal betaine significantly reduced (P < 0.05) plasma CORT concentration and the adrenal expression of vimentin that is involved in trafficking cholesterol to the mitochondria for utilization in offspring pullets. Concurrently, voltage-dependent anion channel 1 and steroidogenic acute regulatory protein, the two mitochondrial proteins involved in cholesterol influx, were both down-regulated at mRNA and protein levels. However, enzymes responsible for steroid syntheses, such as cytochrome P450 family 11 subfamily A member 1 and cytochrome P450 family 21 subfamily A member 2, were significantly (P < 0.05) up-regulated at mRNA or protein levels in the adrenal gland of pullets derived from betaine-supplemented hens. Furthermore, expression of transcription factors, such as steroidogenic factor-1, sterol regulatory element-binding protein 1 and cAMP response element-binding protein, was significantly (P < 0.05) enhanced, together with their downstream target genes, such as 3-hydroxy-3-methyl-glutaryl-coenzyme A reductase, LDL receptor and sterol regulatory element-binding protein cleavage-activating protein. The promoter regions of most steroidogenic genes were significantly (P < 0.05) hypomethylated, although methyl transfer enzymes, such as AHCYL, GNMT1 and BHMT were up-regulated.ConclusionsThese results indicate that the reduced plasma CORT in betaine-supplemented offspring pullets is linked to suppressed cholesterol trafficking into the mitochondria, despite the activation of cholesterol and corticosteroid synthetic genes associated with promoter hypomethylation.

Corticosteroid-Binding Globulin is expressed in the adrenal gland and its absence impairs corticosterone synthesis and secretion in a sex-dependent manner

Corticosteroid-binding globulin (CBG) is synthesized by the liver and secreted into the bloodstream where binds to glucocorticoids. Thus CBG has the role of glucocorticoid transport and free hormone control. In addition, CBG has been detected in some extrahepatic tissues without a known role. CBG-deficient mice show decreased total corticosterone levels with missing of classical sexual dimorphism, increased free corticosterone, higher adrenal gland size and altered HPA axis response to stress. Our aim was to ascertain whether CBG deficiency could affect the endocrine synthetic activity of adrenal gland and if the adrenal gland produces CBG. We determined the expression in adrenal gland of proteins involved in the cholesterol uptake and its transport to mitochondria and the main enzymes involved in the corticosterone, aldosterone and catecholamine synthesis. The results showed that CBG is synthesized in the adrenal gland. CBG-deficiency reduced the expression of ACTH receptor, SRB1 and the main genes involved in the adrenal hormones synthesis, stronger in females resulting in the loss of sexual dimorphism in corticosteroid adrenal synthesis, despite corticosterone content in adrenal glands from CBG-deficient females was similar to wildtype ones. In conclusion, these results point to an unexplored and relevant role of CBG in the adrenal gland functionality related to corticosterone production and release.

Effect of chronic corticosterone treatment on expression and distribution of serotonin 5-HT7 receptors in rat adrenal glands

Sensitized stress-induced corticosterone (CORT) secretion in chronically stressed rats involves 5-HT7 receptor activation. The effect of 14-day chronic CORT and vehicle (VEH) administration on 5-HT7 receptor expression in adrenal glands, adrenal 5-HT content, and adrenocorticotropic hormone and CORT secretion was analysed. On day 15, VEH- and CORT-treated animals were perfused or decapitated without stress exposure (0 min) or after 10 and 30 min of restraint for collection of trunk blood and tissues. 5-HT7 receptor-like immunoreactivity (5-HT7R-LI), 5-HT7 receptor protein, and mRNA levels were determined by immunohistochemistry, Western blot, and reverse transcription polymerase chain reaction assays, respectively; 5-HT levels and hormones were quantified using HPLC and ELISA kits, respectively. An undisturbed control group was included for most experimental comparisons. Chronic CORT strongly increased 5-HT7R-LI in the outer adrenal cortex, as well as 5-HT7 receptor protein and mRNA in whole adrenal glands; adrenal 5-HT content also increased in these animals. Decreased adrenocorticotropic hormone and CORT secretion at 30 min of restraint occurred in CORT-treated rats. The results support the notion that chronic stress-induced increase of adrenocortical 5-HT7 receptors and adrenal 5-HT content is a glucocorticoid-dependent phenomenon; the development of magnified stress-induced 5-HT7 receptor-mediated CORT responses in chronically stressed animals nevertheless likely involves additional mechanisms.

SAT-358 Corticosterone Treatment during Sepsis Results in a Primary Adrenal Defect in Male Survivors

Abnormalities of adrenal gland function have been described in survivors of prolonged critical illness, but whether an acute inflammatory illness such as sepsis causes lasting changes in adrenal function is unknown. Critically ill patients with sepsis are often treated with high doses of corticosteroids for their vasoactive properties, which may also affect adrenal function. To examine the effect of sepsis and corticosteroid treatment on adrenal function, we used a naturalistic mouse model of sepsis, cecal ligation and puncture (CLP). Male and female C57Bl/6 mice (N = 20 per group, 10 male/10 female) underwent CLP or sham surgery and were treated with daily injections of either corticosterone (13 mg/kg) or vehicle for five days. Mice were maintained on a 14:10 light-dark cycle with lights on at 6 AM. Three weeks after surgery, mice were sacrificed at baseline (between 9:00 and 12:00) or after stress (6-minute swim) and blood collected for hormone measurements. Adrenal weights, adrenal gland histology, and gene expression analysis were performed on a subset of mice. The results showed that female mice had higher adrenal weights and higher plasma corticosterone, but lower plasma ACTH, when compared to males. Corticosterone and CLP had sex-dependent effects on adrenal function. Specifically, corticosterone-treated male sepsis survivors had higher morning ACTH/corticosterone ratios than the other groups without any difference in stress ACTH/corticosterone, and this group had heavier adrenal weights. These findings were not explained by adrenal histology. Gene expression analysis of male adrenals showed that corticosterone treatment increased adrenal expression of Sonic Hedgehog, Disabled-2, and COUP-TF in the sham mice, but this effect was absent in sepsis survivors. We conclude that corticosterone treatment during sepsis causes a defect in adrenal function after recovery only in males. The increased ACTH/corticosterone ratio suggests a compensatory increase in pituitary activity, while the gene expression analysis shows an absence of the normal recovery process from corticosterone treatment in the sepsis survivors. These novel findings could have clinical implications for the maintenance of appropriate adrenal function after corticosteroid treatment during acute illness. This work was supported by grants from the NIMH, NIDDK, Office of Naval Research, Hope for Depression Research Foundation, and the Brain and Behavior Research Foundation.

OR02-3 Endocrinological Crosstalk between Calcium Metabolism and Steroidogenesis in Primary Aldosteronism

Introduction Primary aldosteronism (PA) accounts for 5-10% of all of the patients with hypertension and companies higher incidence of cardiovascular events. Calcium metabolic disorders including secondary hyperparathyroidism and osteoporosis were detected more frequently in PA patients than EH patients. Recently, it has been also reported that there was some interactive regulations between parathyroid gland and adrenal zona glomerulosa. However, its detailed mechanism has virtually remained unknown. Therefore, in order to clarify the association between Ca metabolic disorders and steroidogenesis as well as its clinical significance in PA patients, we analyzed expression profiles of Ca-related receptors in aldosterone-producing adenoma (APA), and compared the findings with clinicopathological parameters. PTH-induced steroidogenesis was also examined by in vitro study using H295R cell lines. Materials and methods Thirty formalin-fixed and paraffin-embeded APA and seventeen normal adrenal glands (NA) were examined for immunohistochemistry(IHC). 17 APA and 19 CPA cases were examined for mRNA expression levels of steroidogenic enzymes and Ca-related receptors by qRT-PCR. In vitro study was performed to analyze the responsiveness of steroidogenic enzymes by PTH treatment in H295R. Results Based on the results of IHC analysis, PTH1R and VDR were predominantly immunolocolized in the ZG among the normal adrenal cortex. VDR was positively correlated with CYP21A in normal ZG and CYP11B2 in APA. PTH1R was positively correlated with both CYP11B2 and CYP21A in APA. CaSR was inversely correlated with that of CYP11B2 in normal ZG. Both PTH1R and VDR mRNA levels were significantly higher in APA than in CPA. Also, their mRNA levels were positively correlated with CYP17A in APA. CaSR mRNA was detected in both APA and NA. For the clinical significance, VDR immunoreactivity was positively correlated with TRACP-5b. CaSR immunoreactivity was positively correlated with Bone Mineral Density (BMD). PTH1R immunoreactivity was inversely correlated with serum Ca level, and PTH1R mRNA level was positively correlated with urinary Ca. VDR mRNA level was inversely correlated with serum phosphate(P) and upregulated in KCNJ5 mutated APAs than wild type. CYP11A1 and CYP17A mRNA expression levels were significantly increased in cell line by PTH treatment. Discussion Results of our present study did demonstrate that PTH and Vitamin D could act on their receptors in APA, and could possibly activate aberrant pathways of “neoplastic” steroidogenesis including both aldosterone and cortisol, especially in stimulating CYP17A1 and CYP11A1. In addition, extracellular Ca level was closely associated with steroidogenesis in both normal ZG and PA. Finally, adrenal expression profiles of Ca-related receptors (VDR, CaSR and PTH1R) could be the predictive markers of Ca and bone metabolic disorders in PA patients.

Characterization of gene expression in adrenal glands of mice lacking the circadian clock protein PER1

The circadian clock regulates a variety of physiological responses throughout a 24‐hour period. At a molecular level, the clock is governed by four core transcription factors, including PER1 and CRY, which are found in every cell in the human body. All reported circadian clock gene KO mice have a blood pressure (BP) phenotype. Aldosterone, a mineralocorticoid hormone and product of the renin‐angiotensin‐aldosterone system (RAAS), is secreted by the adrenal cortex and leads to increased sodium reabsorption by the kidneys in response to low BP or low blood volume. Previously we reported that 129/sv mice lacking the circadian clock gene Per1 had reduced BP and reduced plasma aldosterone levels associated with decreased expression of HSD3B1, a key enzyme in the steroid hormone synthesis pathway. Conversely, we found that male C57BL/6 Per1 KO mice have higher BP than control mice and develop non‐dipping hypertension (a lack of dip in BP during the rest period) on a high salt diet plus mineralocorticoid treatment. Non‐dipping hypertension has been associated with an increased risk for cardiovascular disease in humans. Interestingly, female Per1 KO mice do not develop non‐dipping hypertension on a high salt diet plus mineralocorticoid treatment. The goal of this study was to determine if expression of genes involved in the aldosterone synthesis pathway is altered in C57BL/6 Per1 KO mice. These deviances could explain the BP phenotype observed at the physiological level in male mice. We obtained adrenal glands from male and female WT and Per1 KO mice at noon (midpoint of the mouse rest phase), the same time at which serum was collected for aldosterone measurements. RNA was isolated from these tissues, converted to cDNA, and mRNA levels of genes involved in circadian rhythm and aldosterone synthesis were measured by quantitative real time PCR (qPCR). Preliminary data show that Cry1 is significantly down‐regulated in female Per1 KO mice by about 50% versus WT (n=5/6 per group, p&lt;0.05). Expression of aldosterone synthesis genes CYP11B and HSD3B1 did not appear to be significantly altered in the adrenal tissue of male or female Per1 KO mice compared to WT. In contrast to what was observed with 129/sv Per1 KO, plasma aldosterone levels did not differ between C57BL/6 Per1 KO vs. WT. The observed difference in Cry1 expression suggests that RAAS and the circadian clock may work together in the maintenance of homeostatic BP. In the future we expect to perform similar experiments using male and female WT and Per1 KO mice adrenal tissue collected at a midnight time point in order to further investigate the communication occurring at the molecular level between RAAS and the circadian clock.Support or Funding InformationNIH/NIDDK 1R01DK109570; The Gatorade Trust through the UF Department of MedicineThis abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Effect of ACTH and hCG on the Expression of Gonadotropin-Inducible Ovarian Transcription Factor 1 (Giot1) Gene in the Rat Adrenal Gland

Gonadotropin-inducible ovarian transcription factor-1 (Giot1) belongs to a family of fast-responsive genes, and gonadotropins rapidly induce its expression in steroidogenic cells of ovaries and testes of rats. Gonadal Giot1 gene expression is regulated by cyclic adenosine monophosphate (cAMP) -dependent protein kinase A pathway, with essential role of orphan nuclear receptor NR4A1 transcription factor (nuclear receptor subfamily 4, group A, member 1). A recent study reports that Giot1 is also expressed in adrenals, however, the mechanism of its regulation in adrenal gland is yet to be identified. Therefore, the aim of this study was to characterise the changes in Giot1 gene expression in male and female rat adrenals using wide range of in vivo and in vitro experimental models. Special emphasis was directed at the Giot1 gene regulation by ACTH and gonadotropin. In our study, we found that ACTH rapidly stimulates Giot1 expression both in vivo and in vitro. However, gonadotropin does not affect the adrenal Giot1 gene expression, presumably due to the low expression of gonadotropin receptor in adrenals. Both testosterone and estradiol administered in vivo had inhibitory effect on Giot1 gene expression in the adrenals of post-gonadectomized adult rats. Further, our studies revealed that the intracellular mechanism of Giot1 gene regulation in rat adrenals is similar to that of gonads. As in the case of gonads, the expression of Giot1 in adrenal gland is regulated by cAMP-dependent signaling pathway with essential role of the NR4A1 transcription factor. The results of our studies suggest that Giot1 may be involved in the regulation of rat adrenocortical steroidogenesis.

Prenatal caffeine ingestion induces long-term alterations in scavenger receptor class B type I expression and glucocorticoid synthesis in adult male offspring rat adrenals

Caffeine is contained within many drinks and food that are consumed daily. Prenatal caffeine ingestion (PCI) is a risk factor for intrauterine growth retardation (IUGR). We previously observed that PCI inhibits scavenger receptor class B type I (SR-BI)-mediated cholesterol uptake in fetal adrenals, subsequently decreasing glucocorticoid synthesis and inducing IUGR. In the present study, we aimed to investigate the long-term effects of PCI on adrenal glucocorticoid synthesis in adult male offspring rats. After establishing the PCI-induced IUGR, adult male offspring was injected intraperitoneally with 5 mg/kg·d lipopolysaccharide (LPS) for 2 days to induce acute stress. We observed persistent inhibition of SR-BI expression in PCI adrenals before and after stress. Compared with the controls, the PCI offspring had higher corticosterone concentrations after stress. The serum cholesterol concentration was stable without intergroup differences before and after stress. The cholesterol concentration in PCI adrenals showed a higher decrease rate than that of the control after stress. In summary, PCI induced long-term alterations in SR-BI expression and glucocorticoid synthesis in adult male offspring rat adrenals. Cholesterol has to be over-consumed in PCI adrenals against acute stress. This study provides an experimental basis to explain the susceptibility of IUGR offspring to metabolic diseases in adults.

Insulin Regulates Adrenal Steroidogenesis by Stabilizing SF-1 Activity

Development of metabolic syndrome is associated with hyperactivity of the HPA axis characterized by elevated levels of circulating adrenal hormones including cortisol and aldosterone. However, the molecular mechanism leading to the dysregulation of the HPA axis is not well elucidated. In this study, we found that insulin regulates adrenal steroidogenesis by increasing the expression and activity of steroidogenic factor 1 (SF-1) both in vitro and in vivo and this insulin effect was partly through inhibition of FoxO1. Specifically, insulin increased the protein and RNA levels of SF-1 and steroidogenic target genes. Further, adrenal SF-1 expression was significantly increased by hyperactivation of insulin signaling in mice. Together with the elevated SF-1 expression in adrenal glands, hyperactivation of insulin signaling led to increased aldosterone and corticosterone levels. On the other hand, suppressing the insulin signaling using streptozotocin markedly reduced the expression of adrenal SF-1 in mice. In addition, overexpression of FoxO1 significantly suppressed SF-1 and its steroidogenic target genes implying that the positive effect of insulin on SF-1 activity might be through suppression of FoxO1 in the adrenal gland. Taken together, these results indicate that insulin regulates adrenal steroidogenesis through coordinated control of SF-1 and FoxO1.

Dietary betaine supplementation increases adrenal expression of steroidogenic acute regulatory protein and yolk deposition of corticosterone in laying hens

Betaine, an important methyl donor, is known to execute epigenetic regulation of gene expression via nutritional reprogramming. Herein, we explore whether feeding a betaine-supplemented diet to laying hens would affect corticosteroid biosynthesis in the adrenal gland and corticosterone deposition in eggs, in correlation with the expression of methyl transfer enzymes and the promoter DNA methylation status of affected genes. Rugao yellow-feathered laying hens at 38 weeks of age were assigned to Control and Betaine groups, fed basal and betaine-supplemented diets, respectively, for four weeks. Betaine supplementation significantly increased (P <0.05) the average laying rate, while the body weight and egg quality remained unchanged. Plasma concentrations of cholesterol and low-density lipoprotein-cholesterol were also higher (P <0.05) in the Betaine group. Moreover, eggs in the Betaine group contained higher corticosterone in the yolk, which was associated with up-regulation of steroidogenesis genes in adrenal glands. Steroidogenic acute regulatory protein (StAR), the rate-limiting protein responsible for transporting cholesterol to the inner mitochondrial membrane, was significantly activated (P <0.05), together with its transcription factors steroidogenic factor-1 (SF-1) and glucocorticoid receptor. Also, betaine supplementation significantly up-regulated (P <0.05) the adrenal mRNA expression of adenosyl homocysteinase-like 1 and DNA methyltransferases1 and 3a. Bisulfite sequencing analysis revealed significant hypomethylation in several CpG sites within the promoter region of SF-1 gene in the adrenal gland. These results indicate that dietary supplementation of betaine in hens activates adrenal expression of StAR, possibly through epigenetic regulation of SF-1 gene.

Neonatal overfeeding increases capacity for catecholamine biosynthesis from the adrenal gland acutely and long-term in the male rat.

A poor nutritional environment during early development has long been known to increase disease susceptibility later in life. We have previously shown that rats that are overfed as neonates (i.e. suckled in small litters (4 pups) relative to control conditions (12 pups)) show dysregulated hypothalamic-pituitary-adrenal axis responses to immune stress in adulthood, particularly due to an altered capacity of the adrenal to respond to an immune challenge. Here we hypothesised that neonatal overfeeding similarly affects the sympathomedullary system, testing this by investigating the biochemical function of tyrosine hydroxylase (TH), the first rate-limiting enzyme in the catecholamine synthesis. We also examined changes in adrenal expression of the leptin receptor and in mitogen-activated protein kinase (MAPK) signalling. During the neonatal period, we saw age-dependent changes in TH activity and phosphorylation, with neonatal overfeeding stimulating increased adrenal TH specific activity at postnatal days 7 and 14, along with a compensatory reduction in total TH protein levels. This increased TH activity was maintained into adulthood where neonatally overfed rats exhibited increased adrenal responsiveness 30min after an immune challenge with lipopolysaccharide, evident in a concomitant increase in TH protein levels and specific activity. Neonatal overfeeding significantly reduced the expression of the leptin receptor in neonatal adrenals at postnatal day 7 and in adult adrenals, but did not affect MAPK signalling. These data suggest neonatal overfeeding alters the capacity of the adrenal to synthesise catecholamines, both acutely and long term, and these effects may be independent of leptin signalling.

Dietary supplementation with essence of chicken enhances daily oscillations in plasma glucocorticoid levels and behavioral adaptation to the phase-shifted environmental light–dark cycle in mice

Maintenance of circadian rhythms is essential to many aspects of human health, including metabolism and neurological and psychiatric well-being. Chronic disruption of circadian clock function is implicated in increasing the risk of metabolic syndrome, cardiovascular events and development of cancers. However, there are little approaches to reinforce the function of circadian clock for prevention of these diseases. Essence of Chicken (EC) is a nutritional supplement that is traditionally made by extracting water soluble substances derived from cooking the whole chicken. In this study, we found that dietary supplementation with EC enhanced circadian oscillation of glucocorticoid secretion in mice, and this was accompanied by enhancement of circadian oscillation in the adrenal expression of steroidogenic acute regulatory (StAR) protein that mediates the rate-limiting step of glucocorticoid synthesis. Furthermore, EC facilitated re-entrainment of behavioral rhythm in mice when phase of the light–dark cycle was suddenly advanced. These results suggest that intake of EC has enhancement effect on circadian clock function in mice, which may contribute to sustain health and also offer new preventive strategies against circadian-related diseases.