Home blood pressure-lowering effect of a non-steroidal mineralocorticoid receptor blocker, esaxerenone, versus trichlormethiazide for uncontrolled hypertension: the EXCITE-HT randomized controlled study.

The EXCITE-HT study aimed to evaluate the efficacy and safety of esaxerenone versus thiazide diuretics (trichlormethiazide) as second-line treatment for Japanese patients with uncontrolled essential hypertension. This was a 12-week, multicenter, randomized, open-label, parallel-group study. The non-inferiority of esaxerenone to trichlormethiazide was confirmed if the upper limit of the two-sided 95% confidence interval (CI) for the difference in systolic blood pressure (SBP)/diastolic blood pressure (DBP) change between groups was below 3.9/2.1 mmHg. A total of 295 and 290 patients were included in the esaxerenone and trichlormethiazide groups, respectively. The non-inferiority of esaxerenone to trichlormethiazide was demonstrated: least squares mean change differences in morning home SBP/DBP at end of treatment (EOT) were -2.2 (95% CI, -3.6, -0.8) mmHg for SBP/-0.6 (-1.4, 0.2) mmHg for DBP. Morning home, bedtime home, and office BP significantly decreased (all p < 0.001) from baseline to EOT in both groups. The urinary albumin-to-creatinine ratio and N-terminal pro-brain natriuretic peptide level decreased from baseline to Week 12 in both groups, with no notable intergroup difference. Serum potassium elevations occurred more frequently with esaxerenone, while serum potassium reductions occurred more with trichlormethiazide. Uric acid elevations were observed in both groups, but more frequently with trichlormethiazide than esaxerenone. No cases of gout occurred in this study. Reductions in estimated glomerular filtration rate were similarly observed in both groups. EXCITE-HT is the first randomized controlled study to demonstrate evidence that esaxerenone is non-inferior to trichlormethiazide as second-line treatment for Japanese patients with uncontrolled essential hypertension, with no new safety concerns. The EXCITE-HT study demonstrated the non-inferiority of esaxerenone to trichlormethiazide in its morning home blood pressure lowering effect and safety profile in Japanese patients with uncontrolled essential hypertension who were previously treated with an angiotensin II receptor blocker or calcium channel blocker.

Efficacy and Safety of Low-dose Spironolactone for Chronic Kidney Disease in Type 2 Diabetes.

CONTEXT: Although adding spironolactone to renin-angiotensin system blockers reduces albuminuria in adults with chronic kidney disease and type 2 diabetes, it increases the risk of hyperkalemia. OBJECTIVE: To assess whether a lower dose of spironolactone (12.5 mg/d) reduces the risk of hyperkalemia while maintaining its effect on reducing albuminemia. DESIGN: Multicenter, open-label, randomized controlled trial. SETTING: This study was conducted from July 2016 to November 2020 in ambulatory care at 3 diabetes medical institutions in Japan. PATIENTS: We enrolled 130 Japanese adults with type 2 diabetes and albuminuria (≥30 mg/gCre), estimated glomerular filtration rate ≥30 mL/min/1.73 m2, and serum potassium level <5.0 mEq/L. INTERVENTIONS: The participants were randomly assigned to the spironolactone-administered and control groups. MAIN OUTCOME MEASURES: Changes in urine albumin-to-creatinine ratio (UACR) from baseline over the 24-week interventional period. RESULTS: The spironolactone group showed a significant reduction in UACR from baseline (mean decrease, 103.47 ± 340.80 mg/gCre) compared with the control group, which showed an increased UACR (mean increase, 63.93 ± 310.14 mg/gCre; P = .0007, Wilcoxon rank-sum test and t test). Although the spironolactone group had a statistically significant increase in serum potassium levels, none of the participants had a potassium level ≥5.5 mEq/L at 24 weeks. Further, participants with a higher initial serum potassium level tended to have a smaller increase (estimate, -0.37, analysis of covariance). CONCLUSIONS: Low-dose spironolactone administration reduced albuminuria without causing hyperkalemia. Spironolactone administration, the oldest known and most cost-effective mineralocorticoid receptor antagonist, at lower doses should be reconsidered.

Prognostic factors of 90-day mortality in older people with healthcare-associated pneumonia.

AIM: The Quick Sequential Organ Failure Assessment, and confusion, urea, respiratory rate, blood pressure and age (CURB-65) scores have been used as prognostic factors of mortality related to healthcare-associated pneumonia. However, aspiration pneumonia remains unclear. METHODS: A cross-sectional, prospective cohort study was carried out with 130 inpatients aged ≥75 years at a Geriatric ward of Kyorin University Hospital, Japan. We investigated the utility of aspiration pneumonia-related factors, latency of swallowing reflex and cough reflex sensitivity, serum albumin levels, the neutrophil-to- lymphocyte ratio, and conventional scores of pneumonia severity, for predicting 30- and 90-day healthcare-associated pneumonia mortality. Patient demographics, cognition, physical activity (Barthel Index), eating ability (Food Intake Level Scale), dementia stage (Functional Assessment Staging Tool), performance status (Zubrod score), current medications and comorbidities were collected. Pneumonia severity was evaluated using the Quick Sequential Organ Failure Assessment, CURB-65 and Systemic Inflammatory Response Syndrome criteria scores. RESULTS: Age, Barthel Index, Zubrod, Functional Assessment Staging Tool and Food Intake Level Scale scores were significantly associated with mortality, whereas the conventional scores were not. The Kaplan-Meier method with the log-rank test using Cox proportional hazards analysis showed that serum albumin levels <2.75 and the comorbidity of atrial fibrillation were associated with a lower survival rate in deceased versus surviving individuals at 90 days. In addition, a deteriorated latency of swallowing reflex and a blunted cough reflex sensitivity were associated with 90-day mortality. CONCLUSIONS: Hypoalbuminemia, atrial fibrillation, deteriorated latency of swallowing reflex and blunted cough reflex sensitivity values were better predictors of 90-day mortality than traditional scores in older individuals with healthcare-associated pneumonia. Geriatr Gerontol Int 2020; 20: 1036-1043..

Startling hyperglycaemia with transient beta cell stunning in a patient with type 2 diabetes.

A 59-year-old woman unaware of having diabetes was transferred due to coma. Upon discovery at home, her consciousness on the Glasgow Coma Scale was E1V2M4, BP 95/84 mmHg, body temperature 34.7°C. On arrival at ER, height was 1.63 m, weight 97 kg, plasma glucose (PG) 1,897 mg/dL, HbA1c 13.6%, osmolality 421 mosm/kg, arterial pH 7.185, lactate 6.34 mmol/L, ß-hydroxybutyrate 7.93 mmol/L. With saline and regular insulin infusion, PG was lowered to 1,440 mg/dL at 2 hours and then to 250 mg/dL by Day 3, and consciousness normalized by Day 5. On admission, serum immunoreactive insulin (IRI) was undetectable (<0.03 U/mL), C-peptide immunoreactivity (CPR) undetectable (<0.003 ng/mL), and anti-glutamic acid decarboxylase antibody negative. Following the above-described treatment, fasting PG was 186 mg/dL and CPR 1.94 ng/mL, respectively, on Day 14; 2-h post-breakfast PG 239 mg/dL and CPR 6.28 ng/mL, respectively, on Day 18. The patient discharged on Day 18 with 1,800 kcal diet, 32 U insulin glargine and 40 mg gliclazide. Fifteen months later at outpatient clinic, her HbA1c was 6.9% and 2-h post-breakfast PG 123 mg/dL and CPR 5.30 ng/dL with 750 mg metformin, 10 mg gliclazide and 18 U insulin glargine. Transient, but total cessation of insulin secretion was documented in a patient with type 2 diabetes under severe metabolic decompensation. Swift, sustained recovery of insulin release indicated that lack of insulin at the time of emergency was due to secretory failure, i.e., unresponsive exocytotic machinery or depletion of releasable insulin, rather than loss of beta cells.

The association between eating difficulties and biliary sludge in the gallbladder in older adults with advanced dementia, at end of life.

OBJECTIVES: In clinical settings, untreatable biliary sludge in the gallbladder can be observed in older adults with advanced dementia. The underlying cause of biliary sludge existence in patients with dementia is currently unknown. Therefore, we aimed to investigate the prevalence, risk factors, and related outcomes of biliary sludge formation in the gallbladder of older adults with dementia. DESIGN: Cross-sectional study. SETTING: Geriatric ward of University Hospital in Japan. PARTICIPANTS: Inpatients aged 80 and older living with dementia. MEASUREMENTS: We evaluated the presence of biliary sludge by diagnostic ultrasonography and collected data regarding patient demographic information, cognition (mini-mental state examination [MMSE]), physical activity (Barthel Index), oral food intake (food intake level scale [FILS]), clinical stage of dementia (functional assessment staging [FAST] of dementia), and patient performance status (Zubrod/ Karnofsky score). RESULTS: Male sex, larger gallbladder volume and calories from oral intake were significantly associated with the presence of biliary sludge (P = .02, .02, .002, respectively). There was a significant negative correlation between the FAST stage and the FILS level in all patients (P < .001). More advanced dementia and dysphagia was more likely to be found in patients with Alzheimer disease (AD) with biliary sludge, compared to patients with AD without biliary sludge (FAST 7a, FILS II and FAST 6c, FILS V, respectively, P = .06, 04). A logistic regression analysis revealed that the eating status of FILS I and II, generally called "fasting or anorexia", was a significant risk factor for forming biliary sludge in older adults with dementia (P = .031, odds ratio: 5.25, 95% confidence interval: 1.16-23.72). CONCLUSIONS: Fasting status may be associated with the existence of biliary sludge in older adults with dementia. Therefore, supportive care for eating might be an important solution to comfortable end-of-life care for older adults with advanced dementia.

Repression of insulin gene transcription by indirect genomic signaling via the estrogen receptor in pancreatic beta cells.

The mechanism whereby 17ß-estradiol (E2) mediates insulin gene transcription has not been fully elucidated. In this study, exposure of hamster insulinoma (HIT-T15) cells to 5 × 10-9 to 1 × 10-7 M E2 led to a concentration-dependent decrease of insulin mRNA levels. Transient expression of the estrogen receptor (ER) in HIT-T15 cells revealed that estrogen receptor α (ERα) repressed transcription of the rat insulin II promoter in both ligand-dependent and ligand-independent manners. The N-terminal A/B domain of ERα was not required for either activity. However, the repression was absent with mutated ER lacking the DNA-binding domain. Moreover, introducing mutations in the D-box and P-box of the zinc finger of ER (C227S, C202L) also abolished the repression. Deletion of the insulin promoter region revealed that nucleotide positions - 238 to - 144 (relative to the transcriptional start site) were needed for ER repression of the rat insulin II gene. PDX1- and BETA2-binding sites were required for the repression, but an estrogen response element-like sequence or an AP1 site in the promoter was not involved. In conclusion, we found that estrogen repressed insulin mRNA expression in a beta cell line. In addition, the ER suppressed insulin gene transcription in a ligand-independent matter. These observations suggest ER may regulate insulin transcription by indirect genomic signaling.

Effects of Sitagliptin on Pancreatic Beta-Cells in Type 2 Diabetes With Sulfonylurea Treatment: A Prospective Randomized Study.

BACKGROUND: This prospective randomized, multicenter, open-label, comparative study was performed to analyze the effects of sitagliptin on glycemic control and maintenance of beta-cell function in patients with poorly controlled type 2 diabetes treated with low-dose glimepiride. METHODS: Forty-one patients with type 2 diabetes mellitus treated with low-dose glimepiride (≤ 2 mg/day) were prospectively enrolled in this study (age: 20 - 75 years; hemoglobin A1c (HbA1c): 7.4- 9.4%). The patients were randomized into two groups: the glimepiride (G) group, in which glimepiride dose was increased gradually to 6 mg/day, and the sitagliptin (S) group, in which sitagliptin was added at a dose of 50 mg/day. RESULTS: HbA1c level was significantly decreased after 24 weeks, but not 12 weeks, in the G group, while a significant decrease was seen after 12 weeks in the S group. Although there were no significant differences in HbA1c level at 24 weeks between the two groups (P = 0.057). The overall trend of changes in HbA1c level suggested that the glucose-lowering effects were superior in the S group. Furthermore, a significant change in fasting glucose was seen in the S group, but not in the G group. Glycemic control target was achieved in 36.7% and 16.7% patients in the S group and the G group, respectively. The proinsulin/insulin (P/I) ratio was significantly increased in the G group, whereas it tended to decrease in the S group. After 24 weeks of treatment, no significant difference was observed in the P/I ratio between the two groups, whereas a significant difference was noted in the ΔP/I (amount of change). Albuminuria tended to increase in the G group compared with the S group. CONCLUSION: The results of the present study suggested that sitagliptin effectively lowered hyperglycemia and that it may have a protective effect on pancreatic beta-cells when combined with a low dose of glimepiride. Therefore, sitagliptin may represent a useful combination therapy with low-dose sulfonylurea, not only for achieving glycemic control but also for protection of pancreatic beta-cells.

Efficacy of combination therapy with sitagliptin and low-dose glimepiride in Japanese patients with type 2 diabetes.

BACKGROUND: We examined the effects of combination therapy with 50 mg/day of sitagliptin and low-dose glimepiride (1 mg/day) in patients with type 2 diabetes. METHODS: Twenty-six patients with poorly controlled type 2 diabetes currently taking high-dose glimepiride (≥ 2 mg/day) were enrolled in the study. The dose of glimepiride was reduced to 1 mg/day and 50 mg/day of sitagliptin was added without changing the doses of any other antihyperglycemic agents. The patients were divided into two groups: the low-dose group (2 or 3 mg glimepiride decreased to 1 mg: n = 15) and the high-dose group (4 or 6 mg glimepiride decreased to 1 mg: n = 11). RESULTS: Combination therapy significantly lowered HbA1c after 24 weeks of treatment in both groups. In the low-dose group, 8.1 ± 0.2% decreased to 7.0 ± 0.1%; in the high-dose group, 8.4 ± 0.1% decreased to 7.3 ± 0.2%. The time course of the degree of HbA1c reduction in the high-dose group was almost superimposable on that in the low-dose group. There were no changes in body weight and no hypoglycemia and in either group during the study period. In conclusion, our results suggested that the combination therapy used in the study is both well tolerated and effective. CONCLUSION: This study indicated the usefulness of dipeptidyl peptidase (DPP)-4 inhibitors in Japanese patients with type 2 diabetes, and also reinforces the importance of low doses of sulfonylurea for effective glycemic management.

Design, synthesis, and structure-activity relationship (SAR) of N-[7-(4-hydroxyphenoxy)-6-methylindan-4-yl]malonamic acids as thyroid hormone receptor ß (TRß) selective agonists.

Highly TRß selective thyromimetics have several potential therapeutic applications. Based on the novel indane derivative KTA-439 with high receptor (TRß) and organ (liver) selectivity, a series of thyroid hormone analogues were prepared, in which the isopropyl at the 3'-position was replaced with alkyl and aralkyl moieties of variable lengths and branches. Binding assays for these human TRs and reporter cell assays showed that 2-arylethyl derivatives had higher TRß selectivity than KTA-439. KTA-574, a representative 2-arylethyl derivative, had TRß specificity in a binding assay and exhibited full agonism in a reporter cell assay.

Systematic analysis of risk factors for coronary heart disease in Japanese patients with type 2 diabetes: a matched case-control study.

AIM: To identify predictors of coronary heart disease (CHD) in Japanese patients with type 2 diabetes (T2DM). METHODS: A matched case-control study was performed using 800 patients with T2DM admitted for treatment of hyperglycemia from January 2002 to June 2010. Cases comprised 16 patients who had developed acute myocardial infarction and/or received a coronary artery bypass by June 2010, and controls comprised 48 age- and sex-matched patients without CHD events. The mean age, glycated hemoglobin (HbA1c), and body mass index (BMI) were 61.5 yrs, 9.7% and 24.4 kg/m(2), respectively. The relationship of baseline variables, including lipid values, HbA1c, BMI, blood pressure, fasting blood sugar, 2h-post-breakfast blood sugar, delta blood sugar(0-2h), urinary albumin excretion, estimated glomerular filtration rate and treatment modalities (insulin/sulfonylurea/biguanide), to CHD development was analyzed by conditional logistic regression analysis. RESULTS: Total cholesterol (TC) (OR 2.35, 95%CI 1.11-4.98, p=0.03), non-HDL-cholesterol (OR 3.07, 95%CI 1.33-7.10, p=0.009), LDL-cholesterol (OR 2.84, 95%CI 1.24-6.51, p=0.01), non-HDL-cholesterol/HDL-cholesterol (OR 2.07, 95%CI 1.10-3.90, p=0.02) and LDL-cholesterol/ HDL-cholesterol (OR 2.74, 95%CI 1.22-6.15, p=0.01) were significantly related to CHD. Fold risk increment per 1-SD increase in basal TC, non-HDL-cholesterol, LDL-cholesterol, non-HDL-cholesterol/HDL-cholesterol and LDL-cholesterol/HDL-cholesterol was 2.33, 2.89, 2.52, 2.37 and 2.60, respectively. Only non-HDL-cholesterol was an independent risk factor. From the receiver operating characteristic curve, 3.89 mmol/L non-HDL-C was the best cutoff value. None of the non-lipid variables were significantly related to CHD. CONCLUSION: Non-HDL-cholesterol was the most dominant predictor of the development of CHD in Japanese patients with T2DM.

Discovery of novel indane derivatives as liver-selective thyroid hormone receptor ß (TRß) agonists for the treatment of dyslipidemia.

Thyromimetics that specifically target TRß have been shown to reduce plasma cholesterol levels and avoid atherosclerosis through the promotion of reverse cholesterol transport in an animal model. We designed novel thyromimetics with high receptor (TRß) and organ (liver) selectivity based on the structure of eprotirome (3) and molecular modeling. We found that indane derivatives are potent and dual-selective thyromimetics expected to avoid hypothyroidism in some tissues as well as heart toxicity. KTA-439 (29), a representative indane derivative, showed the same high human TRß selectivity in a binding assay as 3 and higher liver selectivity than 3 in a cholesterol-fed rat model.

Lymphocytic infundibuloneurohypophysitis: long-term follow-up of a case cured with glucocorticoid.

OBJECTIVE: To report a case of infundibuloneurohypophysitis treated with steroid. CLINICAL PRESENTATION: A 65-year-old woman who was well until 4 weeks before admission and was not taking any medication presented with acute development of polydipsia and polyuria. Urinary volume was increased to 4,500 ml/day. She showed elevated serum osmolality and low urine osmolality, together with shortage of antidiuretic hormone. Magnetic resonance imaging (MRI) of the pituitary revealed marked nodular thickening of the neurohypophysis. Endocrinologically, anterior pituitary function appeared normal. Based on these examinations, she was diagnosed as having central diabetes insipidus due to lymphocytic infundibuloneurohypophysitis. INTERVENTION: Prednisolone (1 mg/kg/day, p.o.) and D-deaminovasopressin (5 microg/day, intranasal) were commenced. Ten days after the administration of the agents, MRI showed a dramatic improvement in the thickening of the neurohypophysis. Ten weeks later, abnormalities found in earlier MRI had disappeared. The drugs were withdrawn gradually, and diabetes insipidus ceased 25 weeks later. Recurrence was not seen in the subsequent MRI, and the function of the posterior pituitary gland was completely normalized even 7 years after discontinuation of treatments. CONCLUSION: This case shows that noninvasive diagnosis and appropriate steroid administration can effectively cure lymphocytic infundibuloneurohypophysitis; it is recommended with long-term follow-up.

Acromegaly accompanied by Turner syndrome with 47,XXX/45,X/46,XX mosaicism.

A 33-year-old woman was hospitalized for examination of edematous laryngopharynx. She was acromegalic. A pituitary adenoma with elevated serum levels of growth hormone (GH) and insulin-like growth factor-I (IGF-I) was detected, indicating acromegaly caused by GH-secreting pituitary adenoma. Multiple pigmented nevi were also noted without overt short stature and cubitus valgus. Chromosome analysis revealed that she had contracted Turner syndrome with 47,XXX/45,X/46,XX mosaicism. Transsphenoidal resection of the tumor decreased serum GH and IGF-I levels, but the edema was not improved. Both premature ovarian failure and hypertension appeared after surgery. This case may indicate the important relationships between GH/IGF-I and Turner syndrome.

Administration of recombinant human growth hormone normalizes GH-IGF1 axis and improves malnutrition-related disorders in patients with anorexia nervosa.

High serum level of GH in the presence of low plasma level of insulin-like growth factor-I (IGF-I) is one of the endocrinological features of anorexia nervosa (AN). Whether the amount of endogenous GH is not enough to increase IGF-I is not certain. We studied the effect of recombinant human growth hormone (rhGH) on the GH-IGF-I axis and on malnutrition-related disorders in this syndrome. Twenty patients with AN were divided into two groups; one (N = 13) was given rhGH (0.33 mg/day), and the other (N = 7) was given placebo for 6 or 12 months, respectively. During each treatment, levels of serum GH, plasma IGF-I, serum thyroid hormones, serum cholesterol, fasting plasma glucose and cardiac function were monitored. Changes in body mass index (BMI) and calorie taken were also evaluated. Plasma IGF-I level increased from 74.4 +/- 41.9 to 269.0 +/- 31.2 microg/L (P<0.001) during administration of rhGH, which associated with a decrease in serum GH level from 17.0 +/- 15.0 to 1.6 +/- 0.8 microg/L (P<0.001). Administration of rhGH increased BMI, body temperature, fasting plasma glucose level, and food intake. Serum level of triiodothyronine, but not thyroxine, increased during treatment with rhGH. The treatment decreased serum levels of both total and HDL-cholesterol. Studies with echocardiography showed an increase in cardiac output during the treatment with rhGH. These improvements were not observed in patients treated with placebo. Administration of rhGH is recommended as one of the methods of managing the patients with AN.

Insulin Autoimmune Syndrome possibly caused by alpha lipoic acid.

Insulin Autoimmune Syndrome (IAS) is a rare disease characterized by hypoglycemia and autoantibodies to insulin without prior insulin administration. Here, we report a case of IAS associated with alpha lipoic acid (ALA). The patient is a 55-year-old man. He began to complain of hypoglycemic symptoms after taking ALA. He lost consciousness in the late postprandial period and blood glucose was found to be 27 mg/dl. A high insulin level and high titers of insulin antibodies were detected. His HLA genotype contains DRB1* 0406. As ALA comes to be used widely, the incidence of IAS due to ALA might increase.

Synergistic regulation of the mouse orphan nuclear receptor SHP gene promoter by CLOCK-BMAL1 and LRH-1.

Small heterodimer partner (SHP; NR0B2) is an orphan nuclear receptor and acts as a repressor for wide variety of nuclear hormone receptors. We demonstrated here that mouse SHP mRNA showed a circadian expression pattern in the liver. Transient transfection of the mSHP promoter demonstrated that CLOCK-BMAL1, core circadian clock components, bound to E-box (CACGTG), and stimulated the promoter activity by 4-fold. Liver receptor homologue-1 (LRH-1; NR5A2) stimulated the mSHP promoter, and CLOCK-BMAL1 synergistically enhanced the LRH-1-mediated transactivation. Interestingly, SHP did not affect the CLOCK-BMAL1-mediated promoter activity, but strongly repressed the synergistic activation of CLOCK-BMAL1 and LRH-1. Furthermore, in vitro pull-down assays revealed the existence of direct protein-protein interaction between LRH-1 and CLOCK. In summary, this study shows that CLOCK-BMAL1, LRH-1 and SHP coordinately regulate the mSHP gene to generate the circadian oscillation. The cyclic expression of mSHP may affect daily activity of other nuclear receptors and contribute to circadian liver functions.

Inhibition of LXRalpha signaling by vitamin D receptor: possible role of VDR in bile acid synthesis.

The expression of cholesterol 7alpha-hydroxylase (CYP7alpha), the rate-limiting enzyme in the catabolism of cholesterol to bile acid, is stimulated by oxysterol receptor, liver X receptor alpha (LXRalpha) and negatively regulated by a bile acid receptor, farnesoid X receptor. In the current study, we demonstrated that 1,25-(OH)(2)D3 blunted the LXRalpha-mediated induction of CYP7alpha mRNA in H4IIE rat hepatoma cells. In co-transfection experiments in HepG2 cells, VDR repressed the activity of rat CYP7alpha promoter in a ligand-dependent manner through inhibition of LXRalpha signaling. We also confirmed the ability of VDR to repress LXRalpha transcriptional activation using a synthetic LXRalpha responsive reporter. Deletion analyses revealed that the ligand-binding domain of VDR was required for the suppression and the DNA-binding domain was dispensable. Given the fact that VDR can be activated by the secondary bile acid as well as 1,25-(OH)(2)D3, the crosstalk between LXRalpha and VDR signaling in regulation of bile acid metabolism provides a possible contribution of VDR to modulate bile acid and cholesterol homeostasis, and highlights a physiological function of VDR beyond calcium metabolism in the body.

Expression of thyroid hormone receptor alpha in 3T3-L1 adipocytes; triiodothyronine increases the expression of lipogenic enzyme and triglyceride accumulation.

Thyroid hormone receptors (TR) are members of the nuclear receptor superfamily. There are at least two TR isoforms, TRalpha and TRbeta, which act as mediators of thyroid hormone in tissues. However, the relative expression of each TR isoform in target tissues is still elusive. Herein, we have developed an RT-PCR and restriction enzyme digestion method to determine the expression of TRalpha1 and TRbeta1. We analyzed the expression of TR isoforms in 3T3-L1 preadipocytes induced to differentiate by an adipogenic cocktail in the presence or absence of 100 nM triiodothyronine (T(3)). The TRalpha1 isoform was predominantly expressed in 3T3-L1 adipocytes, and its expression was increased at the stage of development concomitant with the emergence of lipid droplets. Little, if any, TRbeta1 mRNA was detected in adipocytes. Administration of T(3) to the differentiating 3T3-L1 cells enhanced the accumulation of triglyceride. The expression profile of TRalpha1 in T(3)-treated adipocytes was similar to that in non-treated cells. The transcripts of adipogenic factors, CCAAT/enhancer binding protein beta (C/EBPbeta) and peroxisome proliferator activated receptor gamma (PPARgamma), were not altered by T(3). Lipid binding protein, aP2, that is downstream of these transcription factors was also unaffected by T(3). In contrast, the lipogenic enzyme, glyceraldehyde-3-phosphate dehydrogenase mRNA was significantly increased in the presence of T(3). Therefore, T(3) appears to be a hormone capable of modulating the expression of lipogenic enzyme and augments the accumulation of lipid droplets. We conclude that the TRalpha isoform might play an important role in the generation and maintenance of the mature adipocyte phenotype, regulating the expression of lipogenic enzymes.