Background DNA methylation is believed to be maintained in adult somatic cells. Recent findings, however, suggest that all methylation patterns are not stable. We demonstrate that stimulatory signals can change the DNA methylation status around transcription factor binding sites and a transcription start site and activate expression of the aldosterone synthase gene (CYP11B2).Methods and Results DNA methylation of CYP11B2 was analyzed in aldosterone‐producing adenomas, nonfunctioning adrenal adenomas, and adrenal glands and compared with the gene expression levels. CpG dinucleotides in the CYP11B2 promoter were found to be hypormethylated in tissues with high expression, but not in those with low expression, of CYP11B2. Methylation of the CYP11B2 promoter fused to a reporter gene decreased transcriptional activity. Methylation of recognition sequences of transcription factors, including CREB1, NGFIB (NR4A1), and NURR1 (NR4A2) diminished their DNA‐binding activity. A methylated‐CpG‐binding protein MECP2 interacted directly with the methylated CYP11B2 promoter. In rats, low salt intake led to upregulation of CYP11B2 expression and DNA hypomethylation in the adrenal gland. Treatment with angiotensin II type 1 receptor antagonist decreased CYP11B2 expression and led to DNA hypermethylation.Conclusions DNA demethylation may switch the phenotype of CYP11B2 expression from an inactive to an active state and regulate aldosterone biosynthesis.

Background Plasma aldosterone-to-renin ratio (ARR) is popularly used for screening primary aldosteronism (PA). Some medications, including diuretics, are known to have an effect on ARR and cause false-negative and false-positive results in PA screening. Currently, there are no studies on the effects of sodium–glucose cotransporter-2 (SGLT2) inhibitors, which are known to have diuretic effects, on ARR. We aimed to investigate the effects of SGLT2 inhibitors on ARR. Methods We employed a retrospective design; the study was conducted from April 2016 to December 2018 and carried out in three hospitals. Forty patients with diabetes and hypertension were administered SGLT2 inhibitors. ARR was evaluated before 2 to 6 months after the administration of SGLT2 inhibitors to determine their effects on ARR. Results No significant changes in the levels of ARR (90.9 ± 51.6 vs. 81.4 ± 62.9) were found. Body mass index, diastolic blood pressure, heart rate, fasting plasma glucose, and hemoglobin A1c were significantly decreased by SGLT2 inhibitors. Serum creatinine was significantly increased. Conclusion SGLT2 inhibitor administration yielded minimal effects on ARR and did not increase false-negative results in PA screening in patients with diabetes and hypertension more than 2 months after administration.

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Adrenocorticotropic hormone (ACTH) stimulation is recommended in adrenal vein sampling (AVS) for primary aldosteronism (PA) to improve the AVS success rate. However, this method can confound the subtype diagnosis. Gene mutations or pathological characteristics may be related to lateralization by AVS. This study aimed to compare the rate of diagnostic discrepancy by AVS pre- versus post-ACTH stimulation and to investigate the relationship between this discrepancy and findings from immunohistochemical and genetic analyses of PA. We evaluated 195 cases of AVS performed in 2011–2017. All surgical specimens were analyzed genetically and immunohistochemically. Based on the criteria, AVS was successful in 158 patients both pre- and post-ACTH; of these patients, 75 showed diagnostic discrepancies between pre- and post-ACTH. Thus, 19 patients underwent unilateral adrenalectomy, of whom 16 had an aldosterone-producing adenoma (APA) that was positive for CYP11B2 immunostaining. Of them, 10 patients had discordant lateralization between pre- and post-ACTH. In the genetic analysis, the rate of somatic mutations was not significantly different between APA patients with versus without a diagnostic discrepancy. In the immunohistochemical analysis, CYP11B2 levels and the frequency of aldosterone-producing cell clusters (APCCs) in APAs were almost identical between patients with versus without a diagnostic discrepancy. However, both the number and summed area of APCCs in APAs were significantly smaller in patients with concordant results than in those whose diagnosis changed to bilateral PA post-ACTH stimulation. In conclusion, lateralization by AVS was affected by APCCs in the adjacent gland, but not by APA-related factors such as somatic gene mutations.

Aim To characterize subjects with a nonpositive insulinogenic index and longitudinally observe changes in their glucose tolerance. Subjects and Methods A historical cohort study was conducted using data from the medical checkups of public school workers. Indices of insulin secretion and insulin sensitivity derived from oral glucose tolerance test (OGTT) and the incidences of diabetes and impaired glucose tolerance (IGT) were compared among subgroups of subjects with different insulinogenic index (change in insulin/change in glucose over the first 30 min on the OGTT). Results Of the 1464 nondiabetic subjects at baseline, 72 (4.9%) subjects had a nonpositive insulinogenic index: 42 of those subjects had a nonpositive glucose response (ΔGlu0–30 ≤ 0) and 30 had a nonpositive insulin response (ΔIns0–30 ≤ 0). Compared with subjects who had normal glucose tolerance (NGT) with insulinogenic index ≥ 0.4, subjects with a nonpositive glucose response had a higher first-phase Stumvoll and lower incidences of diabetes and IGT based on a log-rank test (p < 0.05), whereas subjects with a nonpositive insulin response had lower indices of insulin secretion and a higher incidence of diabetes (p < 0.05). Conclusions These results demonstrate that in the first 30 min on the OGTT, subjects with a nonpositive insulinogenic index due to a nonpositive glucose response (ΔGlu0–30 ≤ 0) had a lower risk for future diabetes and that subjects with nonpositive insulin response (ΔIns0–30 ≤ 0) had a higher risk for future one.