A Case of 17α-hydroxylase/17,20-lyase Deficiency Diagnosed at 45 Years of Age with Hyperaldosteronism.

17α-hydroxylase deficiency is a type of congenital adrenocortical hyperplasia that is typically diagnosed in childhood or adolescence. It manifests as hypertension with gonadal dysfunction as the primary symptom. We herein report 17α-hydroxylase/17,20-lyase deficiency (17OHD) diagnosed at the age of 45 years. The patient presented with hypertension, irregular menstruation, and hyperaldosteronism. The clinical manifestations of 17OHD vary based on the specific variant pattern of CYP17A1. In this case, the variant was c.157_159 TCC del p. Phe53del, which has been frequently reported in Japan. The enzymatic deficiency due to this variant is partial, leading to a delay in making a correct diagnosis.

Discovery of a novel series of medium-sized cyclic enteropeptidase inhibitors.

Enteropeptidase is located in the duodenum that involved in intestinal protein digestion. We have reported enteropeptidase inhibitors with low systemic exposure. The aim of this study was to discover novel enteropeptidase inhibitors showing more potent in vivo efficacy while retaining low systemic exposure. Inhibitory mechanism-based drug design led us to cyclize ester 2 to medium-sized lactones, showing potent enteropeptidase inhibitory activity and improving the ester stability, thus increasing fecal protein output in vivo. Optimization on the linker between two benzene rings resulted in discovery of ether lactone 6b, exhibiting further enhanced enteropeptidase inhibitory activity and long duration of inhibitory state. Oral administration of 6b in mice significantly elevated fecal protein output compared with the lead 2. In addition, 6b showed low systemic exposure along with low intestinal absorption. Furthermore, we identified the 10-membered lactonization method for scale-up synthesis of 6b, which does not require high-dilution conditions.

Second-Generation AUTACs for Targeted Autophagic Degradation.

Targeted protein degradation via the ubiquitin-proteasome system has emerged as one of the most promising drug discovery modalities. Autophagy, another intracellular degradation system, can target a wide range of nonproteinous substrates as well as proteins, but its application to targeted degradation is still in its infancy. Our previous work revealed a relationship between guanine modification of cysteine residues on intracellular proteins and selective autophagy, resulting in the first autophagy-based degraders, autophagy-targeted chimeras (AUTACs). Based on the research background, all the reported AUTACs compounds contain cysteine as a substructure. Here, we examine the importance of this substructure by conducting SAR studies and report significant improvements in the degrader's activity by replacing cysteine with other moieties. Several derivatives showed sub-µM range degrading activity, demonstrating the increased practical value of AUTACs.

Falsely elevated thyroid hormone levels associated with fibrin interference in patients receiving oral anticoagulant therapy.

OBJECTIVE: Unique clinical courses were observed in two asymptomatic patients receiving warfarin who referred to our hospital because of suspected central hyperthyroidism. We eventually diagnosed these patients with falsely elevated thyroid hormone levels caused by macroscopically invisible fibrin. Although false results caused by fibrin interference in vitro have been identified in various immunoassays, especially in blood samples from patients receiving anticoagulant therapy, no studies on thyroid function testing have been reported. The experience in evaluating these cases prompted us to investigate the independent influence of oral anticoagulants via putative fibrin interference on thyroid function testing. METHODS: We retrospectively reviewed known contributing factors that affect thyroid function testing including age, gender, medication history, body mass index, estimated glomerular filtration rate, smoking status, alcohol consumption, and the seasons of hospital visits from participants who presented the Department of Health Checkup between April 2010 and December 2020. RESULTS: A propensity-matched analysis revealed that the median serum free thyroxine levels under oral anticoagulant were significantly higher (17.9 pmol/L, n = 60) than those without anticoagulants (16.0 pmol/L, n = 60; p < 0.001). It was noted that this difference was the largest among contributing factors we analyzed. No significant differences were noted in serum thyroid-stimulating hormone levels. CONCLUSIONS: We report two patients receiving warfarin with falsely elevated thyroid hormone levels caused by fibrin interference resembling central hyperthyroidism for the first time. Our retrospective study suggests that the medication status of oral anticoagulants should be considered when evaluating thyroid function tests.

Clinical outcomes of 34 patients with resistance to thyroid hormone beta: a twenty-year experience in Japan.

Resistance to thyroid hormone beta (RTHß) caused by germline mutations in genes encoding thyroid hormone receptor beta (TRß) is a rare disorder. Little information is available regarding the clinical experience of this syndrome in Japan. We retrospectively reviewed the records of 34 patients with RTHß (21 adult females and 13 adult males) with positive TRß mutations identified at our division between 2000 and 2020. Of the 24 patients with available clinical history, 10 (41.7%) received inappropriate treatments such as antithyroid drugs, thyroidectomy, or radioactive iodine. Diagnostic delay and inappropriate management of RTHß are still present in Japan. Every patient except one demonstrated thyroid hormone profiles indicative of syndrome of inappropriate secretion of thyrotropin (SITSH), characterized by a hormonal profile of hyperthyroxinemia with a non-suppressed TSH concentration. Since the most common forms of hyperthyroidism including Graves' disease feature elevated thyroid hormone levels with suppressed TSH concentrations, early diagnosis of SITSH is critical for preventing inappropriate management. One patient positive for anti-thyroglobulin antibody (Tg-Ab) and anti-thyroperoxidase antibody (TPO-Ab) showed remarkably elevated TSH (>200 µIU/mL) despite thyroid hormone concentrations within the reference ranges. At least one thyroid autoantibody (Tg-Ab, TPO-Ab, or thyrotropin receptor antibodies) was identified in 37.9% (11/29) of the patients tested. One patient developed overt Graves' disease nine years after RTHß diagnosis. These findings suggest that RTHß is frequently comorbid with additional autoimmune thyroid disorders. Further research is required to identify the most appropriate treatments for RTHß patients who develop a second thyroid disorder.

Retroperitoneal Paraganglioma With Asymptomatic Follicular Lymphoma: A Case Report.

Paraganglioma (PGL) is a rare tumor originating from extra-adrenal paraganglionic chromaffin tissues, and most sympathetic PGLs have excessive catecholamine secretion. However, nonfunctional PGLs are sometimes found. Although malignant PGL is defined by metastasis to nonchromaffin tissues, it is difficult to predict malignancies due to the lack of reliable markers of potential malignancies. We report the case of a 69-year-old Japanese woman with an incidental retroperitoneal tumor and multiple enlarged mesenteric lymph nodes simultaneously. The patient had no subjective symptoms and there were no laboratory findings suggesting catecholamine hypersecretion. Both the retroperitoneal tumor and the enlarged mesenteric lymph nodes showed high accumulation of fluorodeoxyglucose (FDG), whereas metaiodobenzylguanidine (MIBG) was accumulated only at the retroperitoneal tumor. Although a retroperitoneal tumor was diagnosed as nonfunctional PGL by examination including MIBG scintigraphy, the cause of enlarged mesenteric lymph nodes could not be diagnosed by imaging and biochemical tests. As a result of retroperitoneal tumor resection and mesenteric lymph nodes sampling, histopathological examination revealed that a retroperitoneal tumor was PGL and enlarged mesenteric lymph nodes were follicular lymphoma. To reveal an underlying genetic factor, we performed whole exome sequencing of genomic DNA, and we identified 2 possible candidate variants in SDHD and DLST, but the pathogenicity of these variants remains uncertain in the present case. This rare case reinforces the importance of histopathological diagnosis of nonchromaffin tissue lesions in patients with PGL for the appropriate treatment strategy.

Dose-Dependent Influence of Antithyroid Drugs on the Difference in Free Thyroxine Levels between Mothers with Graves' Hyperthyroidism and Their Neonates.

BACKGROUND: Several guidelines have recommended that the use of the lowest effective dose of antithyroid drugs (ATDs) that maintains maternal serum free thyroxine (FT4) levels at or moderately above the upper limit of the reference range is appropriate for fetal euthyroid status. However, little is known about whether ATD dosage affects the difference in serum FT4 levels between the mother and neonate. We conducted a retrospective study at a tertiary hospital in Japan to investigate the dose-dependent influence of ATDs on both maternal and fetal thyroid hormone status. MATERIALS AND METHODS: We retrospectively examined 62 pregnant women who delivered between 2007 and 2016 and were treated for Graves' hyperthyroidism with ATD at any stage during pregnancy. We selected individuals whose data on maternal FT4 level within 4 weeks of their deliveries and cord FT4 level of their infants at the time of delivery were available. Those with multiple pregnancies, iodine or glucocorticoid treatment, and fetal goiter detected by ultrasonography were excluded. RESULTS: After the exclusion criteria were applied, we recruited 40 individuals. The cord FT4 levels were significantly lower than the maternal FT4 levels in patients treated with high-dosage ATDs (methimazole >5 mg daily or propylthiouracil >100 mg daily). However, there were no significant differences between maternal and cord FT4 levels in patients treated with low-dosage ATDs (methimazole ≤5 mg daily or propylthiouracil ≤100 mg daily). We selected 35 individuals whose data on maternal thyrotropin receptor-binding inhibitory immunoglobulin (TBII) level were available. Multiple linear regression analysis adjusted for ATD dosage, maternal TBII level, and gestational period found that ATD dosage was a significant predictor of the difference in serum FT4 levels between the mother and neonate. In terms of maternal complications, multiple logistic regression analysis identified maternal free triiodothyronine (FT3) level as a significant predictor of the incidence of preterm delivery. CONCLUSIONS: We found a dose-dependent influence of ATDs on the difference in serum FT4 levels between mothers with Graves' hyperthyroidism and their neonates. Further studies to evaluate the optimal target FT4 and FT3 levels for the mother and neonate during pregnancy may improve the outcome of pregnant women with Graves' hyperthyroidism.

Impairment of the Hypothalamus-Pituitary-Thyroid Axis Caused by Naturally Occurring GATA2 Mutations In Vitro.

The transcription factor GATA2 regulates gene expression in several cells and tissues, including hematopoietic tissues and the central nervous system. Recent studies revealed that loss-of-function mutations in GATA2 are associated with hematological disorders. Our earlier in vitro studies showed that GATA2 plays an essential role in the hypothalamus-pituitary-thyroid axis (HPT axis) by regulating the genes encoding prepro-thyrotropin-releasing hormone (preproTRH) and thyroid-stimulating hormone ß (TSHß). However, the effect of GATA2 mutants on the transcriptional activity of their promoters remains unelucidated. In this study, we created five human GATA2 mutations (R308P, T354M, R396Q, R398W, and S447R) that were reported to be associated with hematological disorders and analyzed their functional properties, including transactivation potential and DNA-binding capacity toward the preproTRH and the TSHß promoters. Three mutations (T354M, R396Q, and R398W) within the C-terminal zinc-finger domain reduced the basal GATA2 transcriptional activity on both the preproTRH and the TSHß promoters with a significant loss of DNA binding affinity. Interestingly, only the R398W mutation reduced the GATA2 protein expression. Subsequent analysis demonstrated that the R398W mutation possibly facilitated the GATA2 degradation process. R308P and S447R mutants exhibited decreased transcriptional activity under protein kinase C compared to the wild-type protein. In conclusion, we demonstrated that naturally occurring GATA2 mutations impair the HPT axis through differential functional mechanisms in vitro.

Hyperfunctioning Papillary Thyroid Carcinoma with a BRAF Mutation: The First Case Report and a Literature Review.

INTRODUCTION: Hyperfunctioning papillary thyroid carcinoma (PTC) is rare and consequently, little information on its molecular etiology is available. Although BRAF V600E (BRAF c.1799T>A, p.V600E) is a prominent oncogene in PTC, its mutation has not yet been reported in hyperfunctioning PTC. CASE PRESENTATION: Ultrasonography detected a 26-mm nodule in the right lobe of the thyroid gland of a 48-year-old man. Thyroid function tests indicated that he was hyperthyroid with a TSH level of 0.01 mIU/L (reference range: 0.05-5.00) and a free thyroxine level of 23.2 pmol/L (reference range: 11.6-21.9). TSHR autoantibodies were <0.8 IU/L (reference value: <2.0 IU/L). The 99mTc thyroid scintigram revealed a round, right-sided focus of tracer uptake by the nodule with a decreased uptake in the remainder of the gland. The patient underwent total thyroidectomy because fine-needle aspiration cytology revealed a malignancy. The histopathological diagnosis was conventional PTC. Subsequent mutational analysis of BRAF (exon 15), TSHR (exons 1-10), GNAS (exons 7-10), EZH1 (exon 16), KRAS, NRAS, HRAS (codons 12, 13, and 61), and TERT promoter (C250T and C228T) identified a heterozygous point mutation in BRAF V600E in a tumor tissue sample. In addition, we identified a TSHR D727E polymorphism (TSHR c.2181C>G, p.D727E) in both the tumor and the surrounding normal thyroid tissue. DISCUSSION AND CONCLUSIONS: We report a case of hyperfunctioning PTC with a BRAF V600E mutation for the first time. Our literature search yielded 16 cases of hyperfunctioning thyroid carcinoma in which a mutational analysis was conducted. We identified TSHR mutations in 13 of these cases. One case revealed a combination of TSHR and KRAS mutations; the other case revealed a TSHR mutation with a PAX8/PPARG rearrangement. These findings suggest that the concomitant activation of oncogenes (in addition to constitutive activation of the TSHR-cyclic AMP cascade) are associated with the malignant phenotype in hyperfunctioning thyroid nodules.

G ATA2 mediates the negative regulation of the prepro-thyrotropin-releasing hormone gene by liganded T3 receptor ß2 in the rat hypothalamic paraventricular nucleus.

Thyroid hormone (T3) inhibits thyrotropin-releasing hormone (TRH) synthesis in the hypothalamic paraventricular nucleus (PVN). Although the T3 receptor (TR) ß2 is known to mediate the negative regulation of the prepro-TRH gene, its molecular mechanism remains unknown. Our previous studies on the T3-dependent negative regulation of the thyrotropin ß subunit (TSHß) gene suggest that there is a tethering mechanism, whereby liganded TRß2 interferes with the function of the transcription factor, GATA2, a critical activator of the TSHß gene. Interestingly, the transcription factors Sim1 and Arnt2, the determinants of PVN differentiation in the hypothalamus, are reported to induce expression of TRß2 and GATA2 in cultured neuronal cells. Here, we confirmed the expression of the GATA2 protein in the TRH neuron of the rat PVN using immunohistochemistry with an anti-GATA2 antibody. According to an experimental study from transgenic mice, a region of the rat prepro-TRH promoter from nt. -547 to nt. +84 was able to mediate its expression in the PVN. We constructed a chloramphenicol acetyltransferase (CAT) reporter gene containing this promoter sequence (rTRH(547)-CAT) and showed that GATA2 activated the promoter in monkey kidney-derived CV1 cells. Deletion and mutation analyses identified a functional GATA-responsive element (GATA-RE) between nt. -357 and nt. -352. When TRß2 was co-expressed, T3 reduced GATA2-dependent promoter activity to approximately 30%. Unexpectedly, T3-dependent negative regulation was maintained after mutation of the reported negative T3-responsive element, site 4. T3 also inhibited the GATA2-dependent transcription enhanced by cAMP agonist, 8-bromo-cAMP. A rat thyroid medullary carcinoma cell line, CA77, is known to express the preproTRH mRNA. Using a chromatin immunoprecipitation assay with this cell line where GATA2 expression plasmid was transfected, we observed the recognition of the GATA-RE by GATA2. We also confirmed GATA2 binding using gel shift assay with the probe for the GATA-RE. In CA77 cells, the activity of rTRH(547)-CAT was potentiated by overexpression of GATA2, and it was inhibited in a T3-dependent manner. These results suggest that GATA2 transactivates the rat prepro-TRH gene and that liganded TRß2 interferes with this activation via a tethering mechanism as in the case of the TSHß gene.

CCNB2 and AURKA overexpression may cause atypical mitosis in Japanese cortisol-producing adrenocortical carcinoma with TP53 somatic variant.

BACKGROUND: Many genomic analyses of cortisol-producing adrenocortical carcinoma (ACC) have been reported, but very few have come from East Asia. The first objective of this study is to verify the genetic difference with the previous reports by analyzing targeted deep sequencing of 7 Japanese ACC cases using next-generation sequencing (NGS). The second objective is to compare the somatic variant findings identified by NGS analysis with clinical and pathological findings, aiming to acquire new knowledge about the factors that contribute to the poor prognosis of ACC and to find new targets for the treatment of ACC. METHOD: DNA was extracted from ACC tissue of seven patients and two reference blood samples. Targeted deep sequencing was performed using the MiSeq system for 12 genes, and the obtained results were analyzed using MuTect2. The hypothesis was obtained by integrating the somatic variant findings with clinical and pathological data, and it was further verified using The Cancer Genome Atlas (TCGA) dataset for ACC. RESULTS: Six possible pathogenic and one uncertain significance somatic variants including a novel PRKAR1A (NM_002734.4):c.545C>A (p.T182K) variant were found in five of seven cases. By integrating these data with pathological findings, we hypothesized that cases with TP53 variants were more likely to show atypical mitotic figures. Using TCGA dataset, we found that atypical mitotic figures were associated with TP53 somatic variant, and mRNA expression of CCNB2 and AURKA was significantly high in TP53 mutated cases and atypical mitotic figure cases. CONCLUSION: We believe this is the first report that discusses the relationship between atypical mitotic figures and TP53 somatic variant in ACC. We presumed that overexpression of CCNB2 and AURKA mRNA may cause atypical mitosis in TP53 somatic mutated cases. Because AURKA is highly expressed in atypical mitotic cases, it may be an appropriate indicator for AURKA inhibitors.

Influence of thyroid dysfunction on brain natriuretic peptide level in health examination participants.

The tissue-specific circulating markers of thyroid hormone action on cardiac function have not been established. Although the relationship between thyroid function and plasma brain natriuretic peptide (BNP) levels has been evaluated in patients with thyroid disorders, the relationship between these parameters in the general population has not been yet studied. We conducted retrospective cohort study by health examination with concurrent measurements of TSH, free T4, body mass index, systolic blood pressure, hemoglobin, and estimated glomerular filtration rate from participants who visited the Department of Health Checkup, Enshu Hospital between July 2008 and March 2017. After participants with abnormal electrocardiogram and/or any history of cardiac disease were excluded, 2,807 individuals were subjected. Multivariate analyses demonstrated that, when compared to euthyroidism (n = 2,629), the increase in BNP levels was significant in overt thyrotoxicosis (n = 21) but not in subclinical thyrotoxicosis (n = 53) or subclinical hypothyroidism (n = 97). Interestingly, the standardized partial regression coefficient was the smallest for thyroid function category (overt thyrotoxicosis compared to euthyroidisim; ß = 0.048, p = 0.006) among the independent variables including age, body mass index, systolic blood pressure, and hemoglobin. In longitudinal comparison, we identified 986 participants who had sequential data on the measurements and were stable as euthyroidism and subclinical hypothyroidism. Their annual percent change in BNP demonstrated no significant differences. In conclusion, a direct stimulatory effect of thyroid hormone on the secretion (or production) of BNP was confirmed even in a large number of health examination participants.

Liganded T3 receptor ß2 inhibits the positive feedback autoregulation of the gene for GATA2, a transcription factor critical for thyrotropin production.

The serum concentration of thyrotropin (thyroid stimulating hormone, TSH) is drastically reduced by small increase in the levels of thyroid hormones (T3 and its prohormone, T4); however, the mechanism underlying this relationship is unknown. TSH consists of the chorionic gonadotropin α (CGA) and the ß chain (TSHß). The expression of both peptides is induced by the transcription factor GATA2, a determinant of the thyrotroph and gonadotroph differentiation in the pituitary. We previously reported that the liganded T3 receptor (TR) inhibits transactivation activity of GATA2 via a tethering mechanism and proposed that this mechanism, but not binding of TR with a negative T3-responsive element, is the basis for the T3-dependent inhibition of the TSHß and CGA genes. Multiple GATA-responsive elements (GATA-REs) also exist within the GATA2 gene itself and mediate the positive feedback autoregulation of this gene. To elucidate the effect of T3 on this non-linear regulation, we fused the GATA-REs at -3.9 kb or +9.5 kb of the GATA2 gene with the chloramphenicol acetyltransferase reporter gene harbored in its 1S-promoter. These constructs were co-transfected with the expression plasmids for GATA2 and the pituitary specific TR, TRß2, into kidney-derived CV1 cells. We found that liganded TRß2 represses the GATA2-induced transactivation of these reporter genes. Multi-dimensional input function theory revealed that liganded TRß2 functions as a classical transcriptional repressor. Then, we investigated the effect of T3 on the endogenous expression of GATA2 protein and mRNA in the gonadotroph-derived LßT2 cells. In this cell line, T3 reduced GATA2 protein independently of the ubiquitin proteasome system. GATA2 mRNA was drastically suppressed by T3, the concentration of which corresponds to moderate hypothyroidism and euthyroidism. These results suggest that liganded TRß2 inhibits the positive feedback autoregulation of the GATA2 gene; moreover this mechanism plays an important role in the potent reduction of TSH production by T3.

Abnormal thyroid hormone response to TRH in a case of macro-TSH and the cut-off value for screening cases of inappropriate TSH elevation.

A 74-year-old asymptomatic Japanese man with suspected thyroid dysfunction was referred to our hospital. He had an elevated TSH (53.8 mIU/L; reference interval: 0.5-5.0) despite a free T4 (FT4) level (1.4 ng/dL; reference interval: 0.9-1.6). Further analysis revealed macro-TSH. A notable finding was that a 500-µg TRH stimulation test revealed a blunted free T3 (FT3) response despite a prolonged TSH response. Macro-TSH typically presents with inappropriately marked elevation of serum TSH levels compared with other thyroid hormones, as exhibited in our case. However, the level of TSH elevation that might differentiate macro-TSH from subclinical hypothyroidism is poorly known. We retrospectively analyzed 8,183 concurrent measurements of TSH and FT4 in individuals previously examined in our hospital to define the cut-off value for screening cases of inappropriate TSH elevation. FT4 values were rounded off to one decimal place, and the 97.5th percentile of TSH against each FT4 value was calculated. The data of our patient and that of 30 cases of macro-TSH extracted from the English literature were then assessed. When the approximate curve obtained from the 97.5th percentile of TSH values was defined as the cut-off value [Log10TSH = 0.700 + 1.549/{1 + (FT4/0.844)6.854}], 25 of the 31 (80.6%) macro-TSH cases were identified. In conclusion, we report for the first time a case of macro-TSH demonstrating an abnormal FT3 response to TRH. A cut-off value of TSH adjusted to the FT4 level may be a good method of screening for inappropriate TSH elevation (or inappropriate hyperthyrotropinemia) including those caused by macro-TSH.

G-protein-coupled receptor 40 agonist GW9508 potentiates glucose-stimulated insulin secretion through activation of protein kinase Cα and ε in INS-1 cells.

OBJECTIVE: The mechanism by which G-protein-coupled receptor 40 (GPR40) signaling amplifies glucose-stimulated insulin secretion through activation of protein kinase C (PKC) is unknown. We examined whether a GPR40 agonist, GW9508, could stimulate conventional and novel isoforms of PKC at two glucose concentrations (3 mM and 20 mM) in INS-1D cells. METHODS: Using epifluorescence microscopy, we monitored relative changes in the cytosolic fluorescence intensity of Fura2 as a marker of change in intracellular Ca2+ ([Ca2+]i) and relative increases in green fluorescent protein (GFP)-tagged myristoylated alanine-rich C kinase substrate (MARCKS-GFP) as a marker of PKC activation in response to GW9508 at 3 mM and 20 mM glucose. To assess the activation of the two PKC isoforms, relative increases in membrane fluorescence intensity of PKCα-GFP and PKCε-GFP were measured by total internal reflection fluorescence microscopy. Specific inhibitors of each PKC isotype were constructed and synthesized as peptide fusions with the third α-helix of the homeodomain of Antennapedia. RESULTS: At 3 mM glucose, GW9508 induced sustained MARCKS-GFP translocation to the cytosol, irrespective of changes in [Ca2+]i. At 20 mM glucose, GW9508 induced sustained MARCKS-GFP translocation but also transient translocation that followed sharp increases in [Ca2+]i. Although PKCα translocation was rarely observed, PKCε translocation to the plasma membrane was sustained by GW9508 at 3 mM glucose. At 20 mM glucose, GW9508 induced transient translocation of PKCα and sustained translocation as well as transient translocation of PKCε. While the inhibitors (75 µM) of each PKC isotype reduced GW9508-potentiated, glucose-stimulated insulin secretion in INS-1D cells, the PKCε inhibitor had a more potent effect. CONCLUSION: GW9508 activated PKCε but not PKCα at a substimulatory concentration of glucose. Both PKC isotypes were activated at a stimulatory concentration of glucose and contributed to glucose-stimulated insulin secretion in insulin-producing cells.

A case of TSH-secreting pituitary adenoma with cyclic fluctuations in serum TSH levels.

A 29-year-old man was referred to our department due to adrenal insufficiency with the inappropriate secretion of TSH (SITSH). Magnetic resonance imaging revealed a pituitary tumor. A weak TSH response in the TRH test, elevated sex hormone binding globulin (SHBG) levels, and the absence of a family medical history of SITSH or TRß gene mutations supported the diagnosis of TSH-secreting pituitary adenoma (TSHoma). However, complete TSH suppression and a blunted cholesterol response in the T3 suppression test as well as normal glycoprotein α-subunit (α-GSU) levels were not compatible with TSHoma. Since TSH, FT3, and FT4 spontaneously returned to normal ranges after admission, he was discharged. One month after his discharge, thyrotoxicosis with elevated serum TSH levels relapsed. After admission, his serum TSH levels returned to within the normal range. After his discharge from the second admission, his serum TSH levels fluctuated in accordance with serum FT3 and FT4 levels and symptoms, such as palpitations. Ten months after his discharge, he was admitted to our department again due to adrenal insufficiency and thyrotoxicosis with elevated serum TSH levels, suggesting cyclic SITSH. Although resistance to thyroid hormone (RTH) was not completely excluded, the pituitary tumor was removed by transsphenoidal surgery (TSS). A pathological diagnosis confirmed TSHoma. We herein report a case of TSHoma in which serum TSH, FT3, and FT4 levels fluctuated periodically. To the best of our knowledge, this is the first case report of "cyclic TSHoma", which needs to be considered when making a differential diagnosis of SITSH.

The Mechanism of Negative Transcriptional Regulation by Thyroid Hormone: Lessons From the Thyrotropin ß Subunit Gene.

Thyroid hormone (T3) activates (positive regulation) or represses (negative regulation) target genes at the transcriptional level. The molecular mechanism of the former has been elucidated in detail; however, the mechanism for negative regulation has not been established. The best example of the gene that is negatively regulated by T3 is the thyrotropin (thyroid-stimulating hormone) ß subunit (TSHß) gene. Analogous to the T3-responsive element (TRE) in positive regulation, a negative TRE (nTRE) has been postulated in the TSHß gene. However, TSHß promoter analysis, performed in the presence of transcription factors Pit1 and GATA2, which are determinants of thyrotroph differentiation in the pituitary, revealed that the nTRE is dispensable for inhibition by T3. We propose a tethering model in which the T3 receptor is tethered to GATA2 via protein-protein interaction and inhibits GATA2-dependent transactivation of the TSHß gene in a T3-dependent manner.

Discovery of Novel 5-(Piperazine-1-carbonyl)pyridin-2(1H)-one Derivatives as Orally eIF4A3-Selective Inhibitors.

Starting from our previous eIF4A3-selective inhibitor 1a, a novel series of (piperazine-1-carbonyl)pyridin-2(1H)-one derivatives was designed, synthesized, and evaluated for identification of orally bioavailable probe molecules. Compounds 1o and 1q showed improved physicochemical and ADMET profiles, while maintaining potent and subtype-selective eIF4A3 inhibitory potency. In accord with their promising PK profiles and results from initial in vivo PD studies, compounds 1o and 1q showed antitumor efficacy with T/C values of 54% and 29%, respectively, without severe body weight loss. Thus, our novel series of compounds represents promising probe molecules for the in vivo pharmacological study of selective eIF4A3 inhibition.

Design and synthesis of a novel series of orally active, selective somatostatin receptor 2 agonists for the treatment of type 2 diabetes.

The discovery of a novel series of ß-methyltryptophan (ß MeTrp) derivatives as selective and orally active non-peptide somatostatin receptor 2 (SSTR2) agonists for the treatment of Type 2 diabetes is described. In our previous research, Compound A, ß-MeTrp derivative with highly potent and selective SSTR2 agonistic activity IC50 (SSTR2/SSTR5)=0.3/>100 (nM), was identified asa drug candidate for treatment of Type 2 diabetes which lowers significantly plasma glucose level in Wistar fatty rats in its oral administrations. However, as serious increase in AUC and phospholipidosis (PLsis) were observed in its toxicological studies in rats, follow-up compounds were searched to avoid risk of PLsis with reference to their in vitro PLsis potentials evaluated on the basis of accumulation of phospholipids in HepG2 cells exposed to the compounds. It has been found that introduction of a carbonyl group onto the piperidine and piperazine or aniline moiety of compounds A and B reduced markedly the in vitro PLsis potentials. And further modification of the compounds and their evaluation led to a discovery of compounds 3k with lower in vitro PLsis potentials exhibiting lowering effect of hypoglycemia-induced glucagon secretion in SD rats (ED50=1.1mg/kg) and glucose excursion in meal tolerance test in Wistar fatty diabetic rats (MED=3.0mg/kg) in oral administrations. Compound 3k was selected asa new drug candidate of selective and orally active non-peptide SSTR2 agonists for treatment of Type 2 diabetes with low in vivo PLsis potential.